Mechanical Engineering Commons^™

An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping (RFP) is a new solid freeform fabrication process that builds an ice part by rapidly freezing water layer by layer. In this paper, we will present our recent progress in the development of this novel process. An experimental system has been built for conducting the research. It consists of an XY-table and Z-stroke driven by micro-stepping motors and a water dispensing and deposition subsystem which incorporates a solenoid valve and a syringe pump placed inside a freezer. Simple heat transfer analysis is made to help select proper values of process parameters and predict part building failures. Example …

Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A method for assessing the environmental performance of solid freeform fabrication (SFF) based rapid prototyping and rapid tooling processes is presented in this paper. In this method of assessment, each process is divided into a number of life stages. The environmental effect of each process stage is analyzed and evaluated based on an environmental index utilizing the Eco-indicators that were compiled by PreConsultants of the Netherlands. The effects of various life stages are then combined to obtain the environmental performance of a process. In the assessment of SFF processes, we consider the material use in the fabrication of a part, …

Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes a rapid tooling process that integrates solid freeform fabrication (SFF) with electroforming to produce metal tools including molds, dies, and electrical discharge machining (EDM) electrodes. Based on experimental data analysis, the geometry and material of the SFF part, the properties of the electroformed metal, and the process parameters are significant factors that cause inaccuracy in the manufactured tools. Thermomechanical modeling and numerical simulation is used to determine the geometry of the SFF part and the electroform thickness for minimizing the manufacturing time and cost while satisfying the tooling accuracy requirement.

Active Local Volume Displacement Cancellation Of A Vibrating Baffled Beam, Marcellin Zahui

Dissertations

An active noise control apparatus is developed. The device reduces the sound radiated from a vibrating clamped beam. The attenuation of the sound field is obtained through minimization of local volume displacements of the vibrating beam. Two single-input/single-output cancellation devices are used. Each device employs a motion sensor and an acoustic actuator. The actuator is a loudspeaker equipped with a pressure sensor to detect its volume displacement. The motion sensor signal is related to the local volume displacement of the structure which is then reduced by a loudspeaker driven with an equal but opposing volume displacement. The volume displacement sensors …

Development Of Mechanical Properties Micromapping For Composite Polymer Systems, Zheng Huang

Masters Theses

By adoption of classic indentation models (Hertzian, modified Hertzian, Sneddon, JKR), the elastic properties of polymeric material can be measured by AFM. Heterogeneous thin films were fabricated from polymer blends with a wide range of Young's moduli and thermal transition temperature to test the developed procedure. Results show that the micromapping of elastic properties can be obtained concurrently for glassy and rubber phases as well as across the interface with a lateral resolution better than 100 nm. Application of the elasticity micromapping on heterogeneous polymeric materials reveals thermal transition temperature that coincides very well with bulk values. Depth profile also …

Nonlinear Robust Missile Autopilot Design Using Successive Galerkin Approximation, Timothy Mclain, Randal W. Beard

Faculty Publications

The application of a new nonlinear robust control strategy to the design of missile autopilots is presented. The control approach described and demonstrated here is based upon the numerical solution of the Hamilton-Jacobi-Isaacs equation by Successive Galerkin Approximation. Using this approach, feedback controllers are computed by an iterative application of a numerical Galerkin-type PDE solver. Application of this approach to the design of a pitch-axis autopilot for a missile having uncertain pitch moment and lift force is described.

Foundation Sleeve For A Guardrail System, Dean L. Sicking, John D. Reid, John R. Rohde

Department of Mechanical and Materials Engineering: Faculty Publications

A highway guardrail terminal system having horizontally extending guardrail elements mounted on a plurality of posts. Foundation sleeves having an elongated slit along one side retain and support appropriate guardrail posts. A plurality of stiffing ribs extend across the slit at a distal portion of the tube. The sleeves enable a safer and faster removal of broken guardrail posts after vehicular impact.

Adaptive Sampling For Coordinate Metrology, Robert Edgeworth, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

An iterative sampling process for dimensional measurement is presented. The strategy is based upon the use of surface normal measurement data to develop an interpolating curve between sample points. The interpolant is used to select subsequent measurement targets iteratively. The process is repeated until the measurement converges to a complete and accurate evaluation of the surface. The required sample size is proportional to part quality. The most accurate parts will require the least sample points; whereas, lower quality parts will require a greater number of total samples. The method is particularly applicable to measurement of complex surfaces with coordinate measuring …

Successive Galerkin Approximation Of The Isaacs Equation, Timothy Mclain, Randal W. Beard, John T. Wen

Faculty Publications

The successive Galerkin approximation (SGA) algorithm has recently been developed for approximating solutions to the Hamilton-Jacobi-Isaacs equation. The algorithm produces feedback control laws that are stabilizing on a well-defined region of state space. The objective of this paper is to demonstrate the application of the SGA algorithm to two simple examples. The examples serve several purposes: first they illustrate how the algorithm is applied in a setting that is simple enough to write out in detail, second they demonstrate the convergence of the algorithm in a setting where the actual solution can be derived analytically.

Triangulation Rangefinder And Sight Positioning System, Jeffrey Hargrove, William G. Wickham, John E. Briggs

Mechanical Engineering Patents

A rangefinder includes an angle sensitive transducer and a programmed data processor to calculate the distance to a target. In one embodiment, the rangefinder also includes a point-to-point measuring device. Another embodiment provides a linear actuator to selectively move a sight indicator vertically. A yet additional embodiment includes a liquid crystal display which displays information to the user.

Industrial Engineering Made Simple, Deena Daggett, Sema E. Alptekin

Industrial and Manufacturing Engineering

Many high school students these days do not quickly recognize or identify Industrial Engineering (IE) procedures, practices, and products. Recruitment of qualified students into IE programs requires continuous planning, publicizing, and networking. Traditional recruitment efforts have included high school visits, brochures & flyers, and university-sponsored workshops. However, these techniques have only achieved mediocre success. Currently, a need exists for new promotional materials that utilize visual tools and provide a “hands-on” approach. We have developed several exercises that successfully introduce IE. Two such exercises are explained in this paper. The first exercise demonstrates the differences between Assembly line and Cellular Manufacturing …

Jun 1999, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Foundation Account Friends of NE State Museum Newsletter

Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The objective of this study was the research of novel and inexpensive sources of polysaccharides degrading enzymes such as amylases and glucanases from local plants in order to justify their biotechnological applications. The isolation of two l3-amylases and an endo-1,3-ß-D-glucanase was reached using common protein purification methods such as buffer extraction, ammonium sulfate fractionation, ionexchange and gel filtration chromatographies. The methods used were simple and easily reproducible, suggesting the possibilfty of large-scale production. ln the crude extract of Curculigo pilosa tuber, only ß-amylase was detected as starch degrading enzyme and its activity was approximately 282 Uig of fresh material. The …

Successive Galerkin Approximation Of A Nonlinear Optimal Attitude Control, Timothy Mclain, Randal W. Beard, Johnathan Lawton

Faculty Publications

This paper presents the application of the successive Galerkin approximation (SGA) to the Hamilton-Jacobi-Bellman equation to obtain solutions of the optimal attitude control problem. Galerkin's method approximates the value function by a truncated Galerkin series expansion. To do so, a truncated Galerkin basis set is formed. A sufficient number of functions must be included in this Galerkin basis set in order to guarantee that the solution will be a stabilizing control. By increasing the size of the Galerkin basis the quality of the approximation is improved at the cost of rapid growth in the computation load of the SGA. A …

User Evaluation Of Prototype Pv Equipment For Disasters, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Natural disasters, such as hurricanes, floods and tornados, can happen at any time, destroying homes and businesses. One such disaster, Hurricane Andrew, devastated South Florida in 1992, leaving several hundred thousand people homeless. Many people were without electrical service, functional water and sewage systems, communications and medical services for days and weeks in the aftermath of the storm. Emergency management teams, the military, and countless public and private organizations staged a massive relief effort.

In response to the Hurricane Andrew disaster, the staff at the Florida Solar Energy Center, with assistance from Sandia National Laboratories, transported PV-powered equipment to Miami …

Program Plan For Photovoltaic Buildings In Florida, Florida Solar Energy Center, Gerard Ventre

FSEC Energy Research Center®

This document outlines plans developed by the Florida Solar Energy Center (FSEC) to support photovoltaic (PV) building applications in the State through the next decade. Implementation of the plan will be a collaborative effort among the Florida Energy Office (FEO) of the Department of Community Affairs, Sandia National Laboratories (SNL), the photovoltaic industry, nine end-user groups, and FSEC.

Installing Photovoltaic Systems: A Question And Answer Guide For Solar Electric Systems, Florida Solar Energy Center, Fsec Photovoltaic Division

FSEC Energy Research Center®

This Question and Answer Guide for Solar Electric Systems addresses general considerations about photovoltaics (PV) technology and requirements for installing photovoltaic power systems, including building-integrated applications. Contained in this guide are commonly asked questions about the technology, and responses based on current state-of-the-art equipment and industry design practice.

Recommendations For Maximizing Battery Life In Photovoltaic Systems: A Review Of The Lessons Learned, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

This report contains notes, observations and recommendations about the use of batteries in small stand-alone photovoltaic (PV) systems. The conclusions of this work are based on the results of more than a decade's worth of battery testing at the Florida Solar Energy Center and related work with Sandia National Laboratories, the PV industry and user groups. The most critical findings were the relationship between battery state-of-charge and battery life and the importance of an adequate PV array-to-load ratio.

Synthesis And Experimental Testing Of A Nonlinear Optimal Tracking Controller, Timothy Mclain, Randal W. Beard, Christopher A. Bailey

Faculty Publications

This paper presents a novel approach for developing tracking controllers for nonlinear systems. The approach involves the numerical solution, by Galerkin approximation, of the time-varying Hamilton-Jacobi-Bellman (HJB) equation and results in a nonlinear controller approximating the optimal tracking control law for a specified desired trajectory and cost function. Experimental results are presented for a nonlinear pendulum system.

Development Of Icejet Machining Technology, Dimitri V. Shishkin

Theses

This work was concerned with the application of ice powder for material processing. Material cutting and surface cleaning were also studied. As a result, innovative cleaning and etching technology was pioneered. The corresponding technology was designed and demonstrated.

The study involved investigation of water freezing, crushing of generated ice, ice transportation, formation of ice water and ice air streams and, finally, use of this stream for material cutting and cleaning. The theoretical work included investigation of the phase change in water and ice formation, effect of ice temperature on particles behavior and entrainment of ice particles by the water stream. …

Oxygen Permeation Through Composite Oxide-Ion And Electronic Conductors, Kevin Huang, Michael Schroeder, John B. Goodenough

Faculty Publications

Oxygen permeation through composites consisting of four well-known oxide-ion conductors and a noble metal, Pd or Ag, is reported. The oxides were Zr_0.9Y_0.1O_1.95 (YSZ), (Bi_1.75Y_0.25O₃)_0.95(CeO₂)_0.05 (BYC5), Ce_0.8Sm_0.2O_1.9 (SSC), and La_0.8Sr_0.2Ga_0.83Mg_0.17O_2.815 (LSGM). The results show that (BYC5 + Ag) yields the highest oxygen permeation flux, but the composite deteriorates with time. The composites (SSC + Pd), (LSGM + Pd), and (YSZ + Pd) give stable, but relatively lower oxygen permeation flux …

Simulation Of Optimal Drive Systems Consisting Of Gear-Cam Mechanisms With Brushless Dc Servomotors, Norbert Fritz

Dissertations and Theses @ UNI

This study presents the development of flexible tools for the numerical simulation of processing machine drives that consist of servomotors, mechanisms, and machine tools. The simulation allows predicting the motions or vibrations of linkages, forces and torques in joints, motor currents, and system response times as well as evaluating stability and characteristic frequencies of the drive system The simulation tools were implemented as macro components in macro component libraries using the EASY5* Dynamic System Modeling, Simulation, and Analysis software by the Boeing Company. Application of the developed macro components allows fast and efficient modeling of a variety of different drive …

One-Dimensional Mean Line Code Technique To Calculate Stage-By-Stage Compressor Characteristics, Sherri Lynette Smith

Masters Theses

Because modem turbine engines have such complex flow fields, extensive testing is required to ensure stability. The testing of these engines and their components is very expensive. To offset testing costs, computer simulations are often used. Several computer simulations have been developed at Arnold Engineering Development Center for this purpose. These codes require stage-by-stage compressor characteristics in order to simulate flow through a compressor.

A technique to calculate compressor characteristics was developed using a mean line code (MLC). This MLC was modified to include loss and deviation correlations from open literature and to account for the conservation of angular momentum …

Directivity Patterns Of Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs

Durham School of Architectural Engineering and Construction: Faculty Publications

Directivity patterns of acoustic radiation have been measured in the far-field of a violin, excited with an open-frame mechanical bowing machine. Analysis of the directivity patterns confirms that, at frequencies below 600 Hz, the violin radiates omnidirectionally, while above 600 Hz, certain trends are apparent as the patterns become increasingly complex. It is noted that when different strings are excited, the far-field radiation patterns observed at nearly the same frequency are similar, even in higher frequency ranges where modal overlap is high. When the difference in frequency between two directivity patterns exceeds some fraction of a semitone, though, the measured …

Variable Area Inlet For Vehicle Thermal Control, Thomas R. Layne, Milton E. Franke, Darrell B. Ridgedly

AFIT Patents

A variable area inlet structure for a vehicle utilizing ram air for coolant is described which comprises a variable area inlet device in the ram air inlet in the form of a butterfly valve, damper, shutter, or similar structure, a temperature sensor in thermal contact with a component within the vehicle to be cooled by ram air flow, a controller and actuator, responsive to the temperature sensor and operatively connected to the variable area device, for controlling the inlet area in response to the component temperature.

Pv Lighting Systems For Bcc - Evaluation Of Vrla Batteries And Pwm Controls, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

This report presents the initial seven-month performance summary for these 15 PV lighting systems, for the period February 13 through September 15, 1997. During this time, the systems were configured with three types of valve-regulated lead acid (VRLA) batteries (five systems using each type of battery), all operating with pulse-width-modulated (PWM) battery charge controllers. Details of the system configurations are presented in this report. Prior to initial operation, extensive baseline data was collected on the individual components installed in each system. This data included battery capacity and high-rate load measurements, battery weights, charge controller set points, PV array currents and …

Ole Miss Engineer 1999

Ole Miss Engineer

No abstract provided.

Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao

Doctoral Dissertations

The problem of long-term structural behavior of CIPP liners under external hydrostatic pressure has been characterized as a structural instability problem which is induced by time-dependent material deformation or creep. It is also a contact problem since the liner deflection is externally constrained by the host pipe. The intrinsically nonlinear problem is investigated by means of finite element simulation, with emphases on (a) the essential structural behaviors and mechanisms of buckling, and (b) the influences of inelastic material properties (i.e. yield strengths and creep rates) and geometrical parameters on liner's buckling resistance.

A liner first deforms as a free pipe …

Multifield Spectral Analysis Of Human Respiratory Sounds, John William Ray Jr.

Doctoral Dissertations

Computer analysis of human respiratory sounds (phonopneumography) has been attempted since the 1960s with poor results. Steady research efforts by numerous researchers have failed to yield a practical diagnostic tool to replace the physician and the stethoscope. This has been the result of the high degree of variability in proposed analysis parameters from subject to subject.

The purpose of this research is to examine a new approach to phonopneumography by comparing multiple lung fields of the same subject for the same breath in order to develop the diagnostic parameters. This approach has the advantage of allowing the subject to provide …

Graphical Display And Data Structure For Virtual Prototyping, David William Manry

Doctoral Dissertations

One of the goals of engineering firms is to bring better products to market faster. Although concurrent engineering can aid in this endeavor, it requires that all areas of an organization work simultaneously. Thus, current product data must be accessible to everyone.

Virtual prototyping allows this simultaneous exchange of information. Virtual prototyping not only replaces the physical model in product development with a virtual model, but also it goes further by allowing data associated with each part of the model to be accessed. This data is not limited to just geometric properties but could contain other quantifiable properties, such as …