Engineering Commons^™

Nebraska Summary: S432 New Holland Tm140, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Research Highlightsfrom A Large Scale Residential Monitoring Study In A Hot Climate, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

This load research project by a large utility has monitored 204 residences in Central Florida, collecting detailed electricity end-use load data. In each home, 15-minute electric demand data is obtained on total electric power, space heating, cooling, water heating, dryers, cooking and pool energy use. Interior and exterior temperatures were also recorded. This is similar to other detailed end-use data monitored in the U.S. Pacific Northwest in the ELCAP project (Pratt et al., 1989) and the PG&E Appliance Metering Project (Brodsky and McNicoll, 1987). However these data are of a more recent vintage and from a cooling dominated climate.

The …

Using Commercial Finite Element Code Called Abaqus In Modeling Hybrid Constrained Layers Damping Beam Structure And Quantitative Determination Of The Stability Of Implant-Bone Interface Using Resonance Frequency Analysis, Daniel Delgado Jr.

Theses and Dissertations - UTB/UTPA

In Chapter 1, it has been demonstrated that the damping treatments for beam and plate structures are effective, and the vibrational behaviors of the systems considered are influenced by many geometrical and material parameters. This has led to an interest in developing advanced “intelligent” structures. In the past, passive and active damping mechanisms have been used to reduce vibration. The uses of passive constrained layers are limited, but it has dissipative qualities for all the modes of the structure; and the uses of active constrained layers are limited to a single mode control. Recent published papers, many have suggested that …

Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

In precision manufacturing enterprises, machine parts at nonstandard temperatures are often soaked to standard temperature prior to making any dimensional measurements. The soakout times are usually determined using lumped heat-transfer models where the part temperatures are assumed to be uniform. This article discusses conditions under which lumped model assumptions are valid by comparing lumped analyses for various shapes and materials with the more general finite element results. In addition, the effect of ambient temperature cycling on part response is also studied.

Chemical Partitioning During Crystallization And Its Effect On The Microstructure And Magnetic Behavior Of Modified Nd–Fe–B Permanent Magnets, Jeffrey E. Shield, B. B. Kappes, D. J. Branagan, J. Bentley

Department of Mechanical and Materials Engineering: Faculty Publications

In this paper, the effect of alloy composition on the microstructural development of devitrified Nd–Fe–B-based alloys is investigated. While crystallization of simple ternary Nd₂Fe₁₄B resulted in a highly variable microstructure and relatively poor demagnetization behavior, alloying additions, notably Ti and C, were found to significantly refine and homogenize the crystallized microstructure. High spatial resolution energy dispersive X-ray spectroscopy revealed that partitioning to the grain boundaries led to the grain refinement by slowing interface kinetics. The more homogeneous grain structure resulted in improved demagnetization behavior, but segregating elements isolated grains and limited intergranular exchange coupling.

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, Yitung Chen

Transmutation Sciences Materials (TRP)

All technologies for the transmutation of nuclear waste require a large source of neutrons. One of the principal methods of generating these neutrons is by using a particle accelerator to bombard a heavy metal target. One of the more promising designs for particle accelerators for transmutation systems is the Superconducting Radio Frequency (RF) high-current linear accelerator (linac). The power supplies for these systems have three major components: niobium cavities, power couplers, and cryomodules. This research project will develop models to predict the behavior and performance of the niobium cavities, which will then be used to design and optimize the superconducting …

Modeling The Evolution Of Anisotropy In Al-Li Alloys: Application To Al–Li 2090-T8e41, Omar S. Es-Said, Hamid Garmestani, Surya R. Kalindi, L. Williams, Cristiane Maria Basto Bacaltchuk, C. Fountain, Eui W. Lee

Mechanical Engineering Faculty Works

It is widely reported in current literature that the precipitation hardened Al–Li sheet alloys exhibit extremely high anisotropy in yield (and ultimate tensile) strength, which is well beyond what can be explained as purely a consequence of the strong crystallographic texture in the material (e.g. J. Mater. Sci. Eng. A265, 1999, 100). This paper presents a crystal plasticity based modeling framework that will (i) facilitate the segregation of the contributions to the overall anisotropy from crystallographic texture and precipitation hardening, and (ii) correlate the contribution from precipitate hardening to either co-planar slip activity or the non-coplanar slip activity in the …

Automated Robotic Inspection System For Electronic Manufacturing, Roberto Alejandro Balderas

Theses and Dissertations - UTB/UTPA

An automated robotic inspection system for electronic manufacturing has been developed to identify pin defects of IC packages mounted on printed circuit boards using surface mount technology. The automated robotic inspection system consists of two robots, a computer, a CCD camera with frame gabber for image acquisition, and a customized windows program using neural network for on-line defect identification. Gray scale images of the pins on IC packages are acquired using ambient light. The images are filtered and formatted to appropriate size, so that Matlab neural network tool could be used. The images are used to train neural networks using …

Nitriding Of Titanium By Inductively Coupled Plasma, Abdul Hakim Hashim

Student Works (2000-2009)

A RF planar coil inductively coupled plasma syslem (ICP) is used in this project to nitride a commercially pure titanium substrate. The system is powered by a 600 W, 13.56 MHz, 50 Ω RF generator. The impedance matching is achieved by using an air­-core step-down transformer and a tunable vacuum capacitor. The electrical discharge characteristics of argon and argon-nitrogen admixture plasmas are investigated. Coil current, ion density and RF power transferred in the plasma at different pressure are studied. Nitriding of titanium using the system is found to be able to produce θ-TiN, ε-Ti2N and α-Ti(N) layers, as confirmed by …

Computational Simulations Concerning Unsteadiness Attenuation In Axial Turbines, Robert R. Croft

Theses and Dissertations

Axial turbomachines have inherently unstable flow fields due to the interaction between rotating and nonrotating blade rows. In addition, combustor instabilities add considerable stress on the blading via the introduction of localized radial and/or circumferential temperature discontinuities known as hot streaks. To alleviate the losses due to nonconformities within the turbine a computational effort has been undertaken investigating the effects of clocking an imbedded stage in a multi- stage axial turbine and a separate study considering the effects of an imposed temporally oscillating hot streak within a 1 1/2 stage turbine. Time-dependent hot streak results show little relation of rotor …

Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan

Electrical and Computer Engineering Faculty Research & Creative Works

A multilayer neural network (NN) controller in discrete-time is designed to deliver a desired tracking performance for a class of nonlinear systems with input deadzones. This multilayer NN controller has an adaptive critic NN architecture with two NNs for compensating the deadzone nonlinearity and a third NN for approximating the dynamics of the nonlinear system. A reinforcement learning scheme in discrete-time is proposed for the adaptive critic NN deadzone compensator, where the learning is performed based on a certain performance measure, which is supplied from a critic. The adaptive generating NN rejects the errors induced by the deadzone whereas a …

The Effects Of An Interactive Computerized Multimedia Tutorial On Knowledge Gain In Modular Fixturing Design Concepts, Veekit O'Charoen

Dissertations and Theses @ UNI

This study was designed to compare student knowledge gain from learning modular fixturing design concepts by computer tutorial versus traditional lecture. The use of computer tutorial to support engineering and technology classroom instructions has been a major issue for many studies. The undergraduate curricula in engineering and technology are becoming increasingly complex due to the today's modern wide variety of manufacturing processes. The concept of modular fixturing in tool design course is one of the technical competencies which most industries would like graduates to be able to apply their knowledge to real-world problems and situations.

An interactive computerized multimedia tutorial …

Holographically Recorded Photopolymer Diffractive Optical Element For Holographic And Electronic Speckle Pattern Interferometry, Sridhar Guntaka, Vincent Toal, Suzanne Martin

Articles

A diffractive optical element is described that can be used to implement a self-aligning electronic speckle apttern interferometer and holographic interferometer requiring only a laser source and a camera in the optical set-up.

Surface Micromachined Force Gauges: Uncertainty And Reliability, Jonathan W. Wittwer, Troy Gomm, Larry L. Howell

Faculty Publications

Surface micromachining of micro-electro-mechanical systems (MEMS), like all other fabrication processes, has inherent variation that leads to uncertain material and dimensional parameters. By considering the effects of these variations during the design of micro force gauges, the gauge uncertainty and reliability can be estimated. Without means of calibrating micro gauges, these effects are often significant when compared to experimental repeatability. The general force gauge model described in this paper can be used to measure a wide range of forces, and simple design changes can lead to improved accuracy in measurement. A method of probabilistic design is described that is not …

Supersonic Combustion And Mixing Characteristics Of Hydrocarbon Fuels In Screamjet Engines, Ahmed A. Taha

Mechanical & Aerospace Engineering Theses & Dissertations

The combustion characteristics of gaseous propane in supersonic airflow using the rearward-facing step that is swept inward from both end sides is studied. The effect of sweeping the step on the flow field features of propane combustion is investigated.

The study of the supersonic combustion of ethylene is carried out using different combustor configurations, different main fuel equivalence ratios, and different pilot fuel equivalence ratios.

The swept step shows the ability to hold the propane flame in the supersonic air stream without extinction. It was found that the side sweeping of the combustor exhibits the high temperature and combustion products …

Forensic Investigation Of Failed Mast Arms Of Traffic Signal Supported Structures, Genda Chen, Michael G. Barker, D. Scott Mackenzie, Christopher W. Ramsay, Joe Alderson, Lokeswarappa R. Dharani, Jiaqing Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Missouri, 11 traffic signal mast arms fractured at the arm-post weld connection in 7 years. To reduce this fatigue failure, the Missouri Department of Transportation developed a fatigue-resistant weld profile that increases the weld leg and reduces the slope of the weld at the toe. This study investigated causes of the failed arms, compared performance of new and old weld profiles, and suggested retrofitting measures for further investigation. The scope included a metallurgical investigation of one failed field mast arm, laboratory fatigue testing of five prototype mast arms (two new and three old profiles), and laboratory failure analysis of …

Interdisciplinary Graduate Experience: Lessons Learned, Steve Eugene Watkins, V. M. Eller, Josh Corra, M. J. Molander, Bethany Konz, Richard H. Hall, K. Chandrashekhara, Abdeldjelil Belarbi

Electrical and Computer Engineering Faculty Research & Creative Works

Engineers interact in the workplace with technical peers in other disciplines at all stages of design, development, and application. Awareness of the constraints and needs of the other disciplines can be key in many situations. Such interdisciplinary activity and the associated communication are facilitated if the all participants have a solid knowledge of discipline-specific terminology and an understanding of connecting concepts. Consequently, experience relating to interdisciplinary teamwork is a necessary component of engineering education. The Smart Engineering Group at the University of Missouri-Rolla was established to conduct interdisciplinary research and to create interdisciplinary educational resources. The topical interest area is …

Investigation Of Reflective Materials For The Solar Cooker, Florida Solar Energy Center, John Harrison

FSEC Energy Research Center®

A critical task in developing a solar cooker is to identify reflector materials that would be both suitable for this application as well as economical. FSEC has conducted an extensive search for available reflective materials. This has included contacting reflective materials manufacturers as well as national laboratories that are currently working with private industry in developing reflector that can be used primarily on large concentrating solar energy devices. This investigation used a variety of resources. These included the FSEC solar library, web search engines, solar industry catalogs and directories, personal contacts, aluminum industry sources, solar cooker discussion groups, and a …

Horses Damp The Spring In Their Step, Alan M. Wilson, M. Polly Mcguigan, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle–tendon units^{1, 2}.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints^{3, 4}. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the muscle^{5 …}

A Fuzzy Autopilot Design Approach That Utilizes Non-Linear Consequent Terms, Robert Sutton, Paul J. Craven

Journal of Marine Science and Technology–Taiwan

This paper describes the development of a fuzzy autopilot for controlling the non-linear yaw dynamics of an autonomous underwater vehicle (AUV) model. The autopilot design is based on a new approach that uses a Gaussian fuzzy inference mechanism. For the design study, the AUV model is hosted in the MATLAB/Simulink environment. Simulation results are presented which illustrate the potential of this novel methodology.

On A Computational Algorithm To The Hje In Nnlinear H∞ Control, Shr-Shiung Hu, Pao-Hwa Yang, Jeng-Yih Juang

Journal of Marine Science and Technology–Taiwan

The Hamilton-Jacobi equation (HJE) plays an essential role in both classical mechanics and nonlinear H∞ control theory. In this paper, we propose a detailed successive algorithm for finding an approximate solution of the HJE by solving linear equations. A scalar example is given to compare the computational procedures and the accuracy for the proposed approach with some other methods. In addition, the nonlinear H∞ controller design for the inverted pendulum is also included to show the superiority of the nonlinear H∞ controller, as compared with the linear H∞ controller, in the aspect of the robust performance/stability.

Coulomb Friction Applied To Analyze The Cutting Vibration Of Tool On Workpiece, Chein-Shan Liu

Journal of Marine Science and Technology–Taiwan

In this paper we study a single-degree-of-freedom model with the parallel presence of a linear spring and a Coulomb's contact friction device, the mass slider of which is mounted on the belt which running forward at a constant speed. We prove that no matter what the parameters are, the mass upon starting to slide never comes to stick on the belt. The oscillating amplitude of the slider is proportional to the belt running speed υ, and is inverse proportional to the natural frequency ω. In order to depress the vibration amplitude we may either decrease the belt running speed, increase …

Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

A nondestructive evaluation (NDE) technique for inspecting or health monitoring of Structures and/or Specimens by analyzing acoustic emission (AE) signals emitted by the Structures and/or specimens. The method and System ana lyzes acoustic emission (AE) signals emitted by structures and/or Specimens. AE Signals emitted by the Structures and/or Specimens are parametrically filtered as a function of parametric filters corresponding to characteristic waveforms of transient AE classes of predefined AE signals. In para metric analysis, the filtering may be pre- or post-recording. In transient AE analysis, the filtering may be prior to transient recording of the transient signals.

World Wide Web Resources For Materials Science, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The internet makes technical information readily available in ways that were unthinkable a few years ago. This article shows how the World Wide Web (the web) can be used in a Materials Science class to enrich the educational process. Strategies for finding and evaluating information and are discussed. © 2002 Wiley Periodicals, Inc.

A Theory Of Volumetric Growth For Compressible Elastic Biological Materials, Stephen M. Klisch, Timothy J. Van Dyke, Anne Hoger

Mechanical Engineering

A general theory of volumetric growth for compressible elastic materials is presented. The authors derive a complete set of governing equations in the present configuration for an elastic material undergoing a continuous growth process. In particular, they obtain two constitutive restrictions from a work-energy principle. First, the authors show that a growing elastic material behaves as a Green-elastic material. Second, they obtain an expression that relates the stress power due to growth to the rate of energy change due to growth. Then, the governing equations for a small increment of growth are derived from the more general theory. The equations …

Modeling, Fabrication, And Optimization Of Niobium Cavities – Phase I: Quarterly Progress Report August 20, 2001 - November 20, 2001, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Multipacting is one of the major loss mechanisms in rf superconductivity cavities for accelerators. This loss mechanism limits the maximum amount of energy/power supported by the cavities. Optimal designs have been identified in others’ studies. In practice, these designs are not easily manufactured. Chemical etching processes used to polish the cavity walls result in a nonuniform surface etch. A nonuniform surface etch will leave some unclean areas with contaminants and micron size particles. These significantly affect mutipacting. Further, a nonuniform etch will leave areas with damaged grain structure, which is not good for superconducting properties. Typically, the depth of chemical …

Industry Guide To Selecting The Best Residential Window Options For The Florida Climate (Revised), Florida Solar Energy Center, Ross Mccluney

FSEC Energy Research Center®

It used to be said that windows are little more than holes in the insulation. It is true to some extent that poorly insulated and drafty windows in certain climates defeat the purpose of wall insulation. However, modern high performance windows are almost as good as opaque insulated wall sections, at least in terms of total energy savings over long periods of time. In some cases, they can be shown to actually out-perform insulated walls. Of course, they have the priceless additional benefits of providing views to the outdoors and natural daylight illumination indoors important issues of quality and comfort. …

Moisture Problems In Manufactured Housing: Probable Causes And Cures, Florida Solar Energy Center, Neil Moyer

FSEC Energy Research Center®

A significant number of new manufactured houses built to HUD code and located in the hot, humid Southeast are experiencing moisture problems. Soft wallboards, buckled floors, damaged wood molding and extensive mold growth are the most common symptoms. These problems do not respond to the standard service and repair strategies for water intrusion

At the request of four manufacturers, over twenty-five such moisture damaged homes were investigated in 1999 and 2000 to determine likely causes. One time blower door, duct tightness and pressure differential measurements were performed on all homes. Field data on ambient, crawlspace, belly and house temperatures and …

A Study Of Muscle Activation In A Mathematical Model Of The Human Head And Neck, Janet Brelin-Fornari, A. Arabyan

Mechanical Engineering Presentations And Conference Materials

A model of the human head and neck that incorporates active and passive muscles is utilized in the analysis of non-impact loading in high “g” environments. The active muscles have the capability to be activated partially and in different combinations.The model is implemented in MADYMO using lumped parameters and Hill muscles. A comparison of simulation results with experimental data, generated by the Naval Biodynamics Laboratory (NBDL) for neck flexion and rebound, shows excellent agreement for a 15g impulsive load.

Ortho-Planar Linear-Motion Springs, John J. Parise, Larry L. Howell, Spencer P. Magleby

Faculty Publications

This paper presents an ortho-planar spring design that operates by raising or lowering its platform relative to the base with no rotation. The compact nature of the design, and its non-rotating motion, eliminates the problem of rotation against adjoining surfaces and is less sensitive to variation in assemblies than many current compact springs. Nomenclature is presented to identify different configurations, mathematical equations are provided that accurately model the force-defection relationships, and a pneumatic valve positioner application is demonstrated.