Engineering Commons^™

Virtual Reality Modelling Of A Cnc Machine, Damian O'Sullivan

Theses

The increasing importance of training and upgrading skills has led to the use of new interactive technologies in the development of more effective training tools. Previous techniques for training Computer Numerical Control (CNC) machine operators, while excellent for their time, varied from brief inexpensive tutorials to expensive on the job training. A CNC machine uses a computer to perform the functions of the machine using a part program stored in the memory of the computer. This thesis describes a Virtual Reality (VR) model of a CNC milling machine, implemented within a VR environment representing a CNC workshop. Its development and …

An Investigation Using The Finite Element Method Into Bowing & Lean Of The 3rd Stage Turbine Blade Of The Pratt & Whitney Jt8d Gas Turbine Engine, Kevin O'Donoghue

Theses

Following a recent series of failures of overhauled third stage turbine blades in the JT8D- 15A gas turbine engine, new inspection criteria have been introduced by the engine manufacturer Pratt & Whitney. One such inspection checks for airfoil bowing and lean. A blade will bow or lean towards the suction face of the airfoil as a result of creep during engine operation. Third stage turbine blades from the JT8D low pressure turbine have been observed with as much as two millimetres of deflection measured at mid-span. In a geometrically correct T3 blade, the tensile centrifugal load due to engine rotation …

Adjustable Ice Fishing Tip-Up, Ashok Midha

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An ice fishing tip-up includes a base frame adapted to span a hole in a layer of ice over a body of water, and carrying a mast which is extendible through the hole into the water. The mast includes a shaft fixed at its lower end to a spool of fishing line and at its upper end to a cam cylinder with a helical groove formed in its outer surface. A signal staff is spring-biased to a raised position and is movable to a lowered position received in one of the convolutions of the helical groove. A pull on the …

Cell Mapping Based Fuzzy Control Of Car Parking, Tea-Quin Kim, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes the development of a near-optimal fuzzy controller for maneuvering a car in a parking lot. To generate the rules of the fuzzy controller, a cell mapping method is utilized to systematically generate near-optimal trajectories for all possible initial states in the parking lot. Based on the input-output relations of these trajectories, which represent the states and controls of the corresponding cells, a set of fuzzy rules are generated automatically. In order to result in a small number of fuzzy rules from the large amount of numerical information generated by cell mapping, grouping of trajectories is proposed and …

A Study Of The Fundamental Operations Of A Capillary Driven Heat Transfer Device In Both Normal And Low Gravity Part 1-Liquid Slug Formation In Low Gravity, Jeffrey S. Allen, Kevin P. Hallinan, Jack Lekan

Mechanical and Aerospace Engineering Faculty Publications

Research has been conducted to observe the operation of a capillary pumped loop (CPL) in both normal and low gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped heat transport devices in low gravity; specifically; evaporator dryout, are not understood and the available data for analyzing the failures is incomplete.

To observe failure in these devices an idealized experimental CPL was configured for testing in both a normal-gravity and a low-gravity environment. The experimental test loop was constructed completely of Pyrex tubing to allow for visualization of system operations. Heat was added to …

Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

The stability of numerical methods used for finite-difference thermal modelling of buildings is discussed. A known instability in a commonly used process is described and alternative numerical methods with suitable stability properties are identified. With a view to selecting the optimum numerical method, the building energy simulation problem is characterized mathematically and appropriate implicit solvers are compared on the basis of accuracy and computational effort using a building related test problem prepared for this purpose. A recently developed numerical method with the necessary strong stability is found to possess higher computational efficiency than methods frequently used in this application and …

Nebraska Summary 287: John Deere 6210 Powrquad Diesel 16-Speed, 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 288: John Deere 6310 Syncroplus Diesel 12-Speed, 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 1898: Case Ih Cx 90/Case Ih C90/Mccormick C 90 & Cx 90 & Cx 95 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1800: Challenger Mt 465 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Sr‐ And Ni‐Doped Lacoo3 And Lafeo3 Perovskites: New Cathode Materials For Solid‐Oxide Fuel Cells, Kevin Huang, Hee Y. Lee, John B. Goodenough

Faculty Publications

An improved cathode material for a solid‐oxide fuel cell would be a mixed electronic and oxide‐ion conductor with a good catalytic activity for oxygen reduction at an operating temperature T _op ≥ 700°C and a thermal expansion matched to that of the electrolyte and interconnect. We report on the properties of Sr‐ and Ni‐doped LaCoO₃ and LaFeO₃ perovskites that meet these criteria. Single‐phase regions were determined by X‐ray diffraction, and thermogravimetric analysis measurements were used to obtain the temperatures above which oxygen loss, and hence oxide‐ion conductivity, occurs. The conductivity and Seebeck measurements indicate the coexistence of both …

Nebraska Summary: S283 New Holland 9682, 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 1759: White 8310 Diesel 32-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Measured And Simulated Performance Of Reflective Roofing Systems In Residential Buildings, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A series of experiments in Florida residences have measured the impact on space cooling of increasing roof solar reflectance. In tests on 11 homes with the roof color changed mid summer, the average cooling energy use was reduced by 19%. Measurements and infrared thermography showed that a significant part of the savings were due to interactions when the duct system is located in the attic space. An improved residential attic and duct simulation model, taking these experimental results into account, has been implemented in the DOE-2.1E building energy simulation program. The model was then used to estimate the impact of …

Belted Work Machine, J. J. Burckhartzmeyer, E. R. Crabb, T. F. Lehnhoff, A. L. Watson Jr.

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A heavy duty belt laying work machine includes a frame, a driver wheel mounted in supporting relation to the frame on each lateral side thereof, an idler wheel assembly disposed on each lateral side of the frame. The idler wheel assembly includes an idler wheel and a carry-roller, each of which is rotatably connected to an idler support arm that is pivotally mounted in supporting relation to the frame. A mid-roller is disposed on each lateral side of the frame between the driver wheel and the idler wheel assembly and rotatably connected to a mid-roller support arm mounted in supporting …

Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks In Time Domain, Jie Shen, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A variant of the Hopfield network, called the modified Hopfield network is formulated. This network which consists of two mutually recurrent networks has more free parameters than the well-known Hopfield network. Stability analysis of this network is presented. The analysis is carried out in the time domain with an application of the Lyapunov method and robust control Lyapunov function. The current flow in the network is treated as a "control". This "controller" is shown to guarantee "a practically stabilizing control". Analysis of the Hopfield network is also included for completion.

An Evaluation Of The Aws Entry Level Welder Training Program, John R. Rice

Dissertations and Theses @ UNI

The purpose of this study was to evaluate the effectiveness of a training program for Entry Level Welders and to provide this information to the American Welding Society (AWS), industry, and educators. The problem of this study was to evaluate the AWS Entry Level Welder Training Program (ELWTP) by obtaining the opinions of faculty members who taught the program and welders who had completed the program.

Two groups comprised the research population for this study. The first group consisted of faculty members who were actually involved in teaching the course at institutions accredited by the AWS to offer the curriculum. …

Aerodynamic Interference For Hypersonic Missiles At Low Angle Of Attack, Harlan F. Nelson, Derek G. Hillstrom

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Euler code is used to predict the flow field over a hypersonic missile and to determine the carryover factors KW(B), fin lift in the presence of the body, and KB(W), lift produced by the body in the presence of the fins. The missile is assumed to have cruciform, delta fins in the + orientation and an aspect ratio of 1.529. Results are presented as a function of fin span at Mach 6, 8, and 10, for a 2-deg angle of attack. Two ratios of specific heats, 1.4 and 1.3, are considered to partially account for vibrational excitation effects. Both …

Test 1770: Challenger Mt 655 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1803: Kubota M6800dt Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1805: Kubota M9000dt Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1774: Zetor 10641/Zetor 10741 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1747: John Deere 8400t Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE

General

Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure.

The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Nebraska Summary 271: Agco Rt145 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1896: Case Ih Cx 80/C 80 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1898: Ih Cx 90/C 90 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1899: Case Ih Cx 100/C 100 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1895: Case Ih Cx 70/Case Ih C 70/Mccormick C 70 & Cx 70 & Cx 75 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1896: Case Ih Cx 80/Case Ih C80/Mccormick C 80 & Cx 80 & Cx 85 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1816: New Holland 9682 Quadrasync Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.