Mechanical Engineering Commons^™

Nebraska Summary: S407 Case-Ih Jx80u, 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 …

Nebraska Summary: S404 Case-Ih Jx75, 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 …

Nebraska Summary: S360 Massey Ferguson 4335, 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 …

Nebraska Summary: S422 Mccormick Mtx 125, 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 …

Test 1814: Challenger Mt855 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Using Spreadsheet Programs In Teaching Machine Design, Cheng Y. Lin, Gary R. Crossman

Engineering Technology Faculty Publications

This paper presents an approach on using spreadsheets to teach machine design. It also lists detailed procedures on how to implement the teaching scheme. Results show that spreadsheet programs can help students organize their design procedures. By using the characteristics of spreadsheet programs, students do not have to repeat the same calculation and can get the alternate solution of a design almost instantly when given different values on the inputs. When compared to the method taught by using calculators, students can significantly improve their performance on homework problems and tests. From teaching evaluations, their interest in taking such a course …

A New Method For Suboptimal Control Of A Class Of Nonlinear Systems, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique (θ - D approximation) is presented. This approach achieves suboptimal solutions to nonlinear optimal control problems in the sense that it solves the Hamilton-Jacobi-Bellman (HJB) equation approximately by adding perturbations to the cost function. By manipulating the perturbation terms both semi-globally asymptotic stability and suboptimality properties can be obtained. The convergence and stability proofs are given. This method overcomes the large control for large initial states problem that occurs in some other Taylor expansion based methods. It does not need time-consuming online computations like the state dependent Riccati equation (SDRE) technique. …

Modeling, Fabrication, And Optimization Of Niobium Cavities: Phase Ii Second Quarterly Report, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells are the most appropriate shape for superconducting cavities. The need for very clean surfaces lead to the use of a buffered chemical polishing produce for surface cleaning to get good performance of the cavities. Up to this point, the second phase has resulted in the design of an experimental setup for the fluid flow experiment. Other experimental activities include the evaluation of a vacuum system are underway. Little reportable progress has …

A New Approach To Evaluate Fracture Strength Of Uv-Liga Fabricated Nickel Specimens, Catherine Oropeza

LSU Master's Theses

One of the major difficulties faced by MEMS researchers today is the lack of data regarding properties of electroplated metals or alloys at micro-levels as those produced by the LIGA and LIGA related process. These mechanical properties are not well known and they cannot be extrapolated from macro-scale data without experimental verification. This lack of technical information about microscale physical properties has affected the consistency and reliability of batch-fabricated components and leads to very low rates of successful fabrication. Therefore, this material issue is of vital importance to the development of LIGA technology and to its industrial applications. This thesis …

A Functional Basis For Engineering Design: Reconciling And Evolving Previous Efforts, Julie Hirtz, Robert B. Stone, Daniel A. Mcadams, Simon Szykman, Kristin L. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In engineering design, all products and artifacts have some intended reason behind their existence: the product or artifact function. Functional modeling provides an abstract, yet direct, method for understanding and representing an overall product or artifact function. Functional modeling also strategically guides design activities such as problem decomposition, physical modeling, product architecting, concept generation, and team organization. A formal function representation is needed to support functional modeling, and a standardized set of function-related terminology leads to repeatable and meaningful results from such a representation. We refer to this representation as a functional basis; in this paper, we seek to reconcile …

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.

A New Filtering Technique For A Class Of Nonlinear Systems, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear filtering technique (θ-D filter) is presented. This filter is derived by constructing the dual of a new nonlinear regulator control technique, θ-D approximation which involves approximate solution to the Hamilton-Jacobi-Bellman equation. The structure of this filter is similar to the state dependent riccati equation filter (SDREF). However, this method does not need time-consuming online computation of the algebraic Riccati equation at each sample time compared with the SDREF. By manipulating the perturbation terms both the asymptotic stability and optimality properties can be obtained. A simple pendulum problem is investigated to demonstrate the effectiveness of …

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 …

Tribological Behavior Of Nanostructured Nickel, Dean Joseph Guidry

LSU Master's Theses

The present study reports the effects of electroplating parameters on the microstructure, and thus the mechanical and tribological properties, of nanostructured nickel. Electroplating was conducted in a Watt's type bath with a pH of 3.0 carried out using direct current in galvanostatic mode at current densities of 30 mA/cm² and 15 mA/cm² in electroplating bath temperatures of 30°C and 50°C. Grain size and distributions were determined from TEM (Transmission Electron Microscope) and SEM (Scanning Electron Microscope) micrographs. Tribological tests were carried out on a pin-on-disc type tribometer. The same tests were conducted on Ni-200 for the purpose of …

Buckling Analysis Of Grid Stiffened Composite Structures, Samuel Kidane

LSU Master's Theses

Buckling of a stiffened composite cylinder is a very complex phenomenon that involves complex interactions between the skin and the stiffeners. Depending on different configurations of the skin and stiffener, different buckling failure modes and failure loads are observed in stiffened cylinders. In this work failure modes and buckling loads of stiffened composite cylinders under uniaxial loading condition is investigated by using analytical and experimental approaches. In the first Chapter an improved smeared method is developed to model the buckling problem of an isogird stiffened composite cylinder. In this model the stiffness contributions of the stiffeners is computed by analyzing …

Tapered Liga Mold Insert, Ryan Anthony Turner

LSU Master's Theses

The applications of microstructures produced by the LIGA process are useful in a broad range of fields including: microfluidics, heat transfer, and mechanics. The Microsystems Engineering Team at Louisiana State University has used the LIGA process as a foundation for the team’s productivity in these areas. Many advances in the processes involved in producing these microstructures have been made in the past increasing the efficiency of the entire process. A modified exposure technique in the lithography stage of the LIGA process is being developed to produce microstructures with a draft angle as opposed to the standard straight walled structures. Electroformed …

Prediction Of Heat Transfer & Flow In Rotating Two-Pass Channels Connected By Holes., Achintya Kumar Pramanick

LSU Master's Theses

A computational study of the effect of rotation on the velocity and thermal field for a two-pass channel connected by rows of holes on the divider wall has been conducted. Detailed velocity and Nusselt number distributions are presented inside the rotating two-pass coolant channel. The enhanced cooling in this passage design is achieved by a combination of impingement and crossflow-induced swirl. The cross flow is generated from one coolant passage to the adjoining coolant passage through a series holes placed along the dividing wall. The holes deliver the flow from one passage to another typically achieved in a conventional design …

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 …

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 …

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 …

Spectral Integration Of Microstructure And Design, Brent L. Adams, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi

Faculty Publications

Support of the Army Research Office is greatly appreciated. Mechanical design can be conducted in a framework where consideration of microstructure as a continuous design variable is facilitated by the use of a Fourier space. Selection of the mechanical framework for the problem (e.g., mechanical constitutive model and homogenization relations) dictates the dimensionality of the pertinent microstructure representation. Microstructure is comprised of basic elements that belong to the local state space. Local state includes crystallographic phase and orientation, and other parameters such as composition. The local state space is transformed into an isomorphic set in Fourier space. The universe of …