Mechanical Engineering Commons^™

A Review Of Hot Water Draw Profiles Used In Performance Analysis Of Residential Domestic Hot Water Systems, Florida Solar Energy Center, Philip Fairey

FSEC Energy Research Center®

As a result of efforts on the part of various organizations to improve the specifications for performance-based analysis of energy use in residences, the literature on residential hot water use has been reviewed, specifically as it relates to typical hot water use draw profiles. A number of daily hot water use draw profiles have been identified and reviewed.

Double Diffusive Convection During Solidification Of Ammonium Chloride - Water (Nh4cl-H20) Mixture In A Trapezoidal Cavity, Ravi Kumar Duggirala

FIU Electronic Theses and Dissertations

The effect of the initial concentration of ammonium chloride (sub eutectic: C < 19.8 wt. % and eutectic C_e= 19.8 wt. %) and boundary temperatures (T_cold = -30 ⁰C to -10 ⁰C) on the solidification process is examined. Particle Image Velocimetry (PIV) is used in this study to measure the velocity fields in the melt during the solidification process. The distributions of temperatures at discrete locations in the solution and the boundary walls were measured. This study focuses on the solidification of an ammonium chloride-water (NH₄Cl- H₂O) solution in a trapezoidal cavity with one and two inclined cooling …

Effect Of Chromium-Gold And Titanium-Titanium Nitride-Platinum-Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications require good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr/Au and Ti/TiN/Pt/Au metallization systems. Both chromium and titanium are used to promote adhesion between substrates and sputtered gold films. Both can diffuse the gold surface after annealing and degrade the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr/Au and Ti/TiN/Pt/Au, annealing, and CAN etch processes on 25.4 times; 254 μm (1 × 10 mil) ribbon bonding. All bonds were …

Assuring Power In A Disaster And Providing Energy Security, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Daily use of a myriad of electrical and electronic devices has contributed to a steadily increasing dependence on electric power. The degree of importance of electricity is temporarily highlighted with any type of power outage, whether caused by a disaster as destructive as a Hurricane Andrew or as minor as an afternoon thunderstorm knocking down local utility lines. After September 11, terrorism added a new dimension to our definition of energy security. While the American public is dependent on utility providers to meet energy needs, it is the right and the responsibility of each citizen to become aware of energy …

Flexible Machine Tool Control For Direct, In-Process Dimensional Part Inspection, Tyler Addison Davis

Theses and Dissertations

For some time now coordinate measuring machines have been an integral part of the shop floor. The goal has been to make coordinate measuring machines (CMMs) into tools that can easily be used by machinists to improve their manufacturing capabilities. The value of a CMM as a quality control tool is undisputed. Now efforts are being made to further reduce the time and cost of measurement by reducing the physical distance between machining and measuring processes. The ability to reduce that distance to zero and measure a part directly on the chip-making machine has been a goal for many years. …

Admittance Selection For Force-Guided Assembly Of Polyhedral Parts In Single-Point Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

The selection of the proper admittance is important in achieving force-guided assembly. This paper identifies procedures for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for single-point frictionless contact cases. Sets of conditions that are imposed on the admittance matrix for different types of single-point contact are presented. These conditions ensure that the motion that results from contact reduces part misalignment in the selected contact state. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance also satisfy the conditions at all …

Pressure Distribution Around Spherical Distal Ball-Tip In Ultrasound Angioplasty, Graham Gavin, Garrett B. Mcguinness, Finbar Dolan, M.S. J. Hashmi

Conference Papers

INTRODUCTION Ultrasound Angioplasty has been shown to be effective in the removal and re-canalising of blockages in arteries (Siegel RJ, 1993). By delivering therapeutic ultrasound to the blockage, via a wire waveguide to a ball-tip, the lesion or thrombus is affected by pressure waves, micro streaming, cavitation and direct contact with the oscillating ball-tip. Most work to date has concentrated on a spherical ball-tip geometry at the distal end of the wire waveguide (Steffen, 1994 and Rosenschein, 1996). Tip displacements usually lie between 10 - 100m (peak-to peak) and ball tip diameters between 1 - 2mm (Atar, 1999 and Yock, …

Laser Scanning Thermal Probe: A Novel Approach To Non-Destructive Evaluation, Jacob Kephart, John Chen, Hong Zhang

Mechanical Engineering

Structuraldefects such as cracks have recently been identifiable through anew nondestructive evaluation (NDE) technique know as sonic IR orthermosonics. However, these defects are depicted through thermal imagining systemas localized "hot spots" indicating a general location of adefect without an accurate portrayal of the dimensions or shapeof the defect. This paper demonstrates a new technique calledLaser Scanning Thermal Probe, LSTP, which utilizes thermography with theuse of heat application in strategic locations to observe spatialheat flow patterns. The LSTP records heat propagation across adefect area previously identified through the thermosonic technique. Thermal gradientswill occur as heat traverses the crack and provide informationto …

Accreditation Of Mechanical Engineering Education In The Usa In 21st Century, Said Shakerin

All Faculty Articles - School of Engineering and Computer Science

Accreditation board for engineering and technology (ABET) in the USA made a paradigm shift in its accreditation criteria for evaluation of engineering education in 2000. Under the new criteria, called ABET2000, educational programs are evaluated based on thir outcomes as opposed to their contents, which were the mail focus under the old criteria. Engineering education has thus undergone major changes. In this paper, ABET s purpose, its criteria, and the evaluation process are explained, followed by specific industrial.

Flexible Roofing Facility: 2003 Summer Test Results, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The Flexible Roof Facility (FRF) is a test facility in Cocoa, Florida designed to evaluate five roofing systems at a time against a control roof with black shingles and vented attic (Figure E-1). The testing evaluates how roofing systems impact summer residential cooling energy use and peak demand. In the summer of 2003, the following roofing systems were tested: Galvalume® unfinished 5-vee metal with vented attic (2nd year of exposure); sealed attic with proprietary configuration; high reflectance brown metal shingle with vented attic; galvanized unfinished 5-vee metal with vented attic (2nd year of exposure); black shingles with standard attic ventilation …

Unmanned Air Vehicle Testbed For Cooperative Control Experiments, Timothy W. Mclain, Randal W. Beard

Faculty Publications

This paper describes the MAGICC Lab unmanned air vehicle (UAV) testbed at Brigham Young University. Motivation for pursuing experimental research with UAVs is given as well as a historical perspective of the UAV testbed development. Lessons learned through the development and use of the testbed over the past several years are summarized.

New Stereology For The Recovery Of Grain-Boundary Plane Distributions In The Crystal Frame, Brent L. Adams, Ryan J. Larsen

Faculty Publications

One of the authors (RJL) is grateful to the Office of Naval Research for fellowship support. BLA acknowledges the support of the NSF through the Materials Research Science and Engineering Center, Carnegie Mellon University (Grant No. DMR-0079996). A new experimental method is given for recovering the probability-distribution function Sv(ns/g). The function Sv(na/g) is the grain-boundary area per unit volume as a function of grain-boundary plane orientation (na), given a lattice misorientation (g) between the adjoining grains. The grain-boundary normal (na) is expressed in the crystal frame in which the misorientation g originates. The proposed method recovers the three-dimensional Sv(na/g) function …

Uncertainty Propagation And Robust Design In Cfd Using Sensitivity Derivatives, Michele M. Putko

Mechanical & Aerospace Engineering Theses & Dissertations

This study investigates and demonstrates a methodology for uncertainty propagation and robust design in Computational Fluid Dynamics (CFD). Efficient calculation of both first- and second-order sensitivity derivatives is requisite in the proposed methodology. In this study, first- and second-order sensitivity derivatives of code output with respect to code input are obtained through an efficient incremental iterative approach.

An approximate statistical moment method for uncertainty propagation is first demonstrated on a quasi one-dimensional (1-D) Euler CFD code. This method is then extended to a two-dimensional (2-D) subsonic inviscid model airfoil problem. In each application, given statistically independent, random, normally distributed input …

Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue

Mechanical & Aerospace Engineering Theses & Dissertations

Naturally nanofluidics has applications demanding the samples to be handled in exceedingly small quantities due to the small size of the fluidic channels in nanofluidic devices, such as characterization of single biomolecules. Fluids confined in channels of nanometer characteristic dimensions exhibit physical behaviors not observed in large conduits. Charge properties of the nanochannel wall in contact with an aqueous solution play essential roles in the involved electrokinetic transport phenomena occurring in nanofluidic devices. In addition to tuning the charge properties of the nanofluidic channel wall by adjusting the solution properties such as pH and background salt concentration, field effect transistor …

Measuring The Five-Parameter Grain-Boundary Distribution From Observations Of Planar Sections, Brent L. Adams, Bassem S. El-Dasher, Gregory S. Rohrer, David M. Saylor

Faculty Publications

One of the authors (DMS) thanks his colleagues at NIST, Edwin R. Fuller, Jr. and Grady S. White, for their helpful advice and criticisms, as well as Mark D. Vaudin and James A. Warren for their critical review of this manuscript. This work was supported at CMU by the MRSEC program of the National Science Foundation under Award No. DMR-0079996. A sterological method is described for estimating the distribution of grain-boundary types in poly-crystalline materials on the basis of observations from a single planar section. The grain-boundary distribution is expressed in terms of five macroscopically observable parameters that include: three …

The Development Of Web-Based Aerobic And Anaerobic And Muscle Static Work Capacity Modules Using Legacy Cycle Approach, Anant Ravindra Deshpande

Theses and Dissertations - UTB/UTPA

The Legacy cycle is an instructional model that emphasizes inquiry. Learners are faced with progressively complex challenges. For each challenge, learners generate initial thoughts on how they might react to the challenges. In this thesis, a web based instructional method that evaluates interactivity and motivation is presented. The system presented in the thesis helps student to integrate the use of legacy cycle approach in the regular study of aerobic and anaerobic and muscle static work capacity modules. The thesis also focuses on developing modules which contain challenges encompassing various sections, which helps student as an asynchronous learning tool, intended for …

Wind Shear, Christopher Roman

Christopher N. Roman

Article that appeared in Sail magazine (ISSN: 0036-2700).

A Genetic Algorithm Approach For Model Reference Adaptive Control Of Ionic Polymer Metal Composites, Brijesh C. Lavu, Marco P. Schoen, Ajay Mahajan

Mechanical Engineering Faculty Research

Electroactive polymers undergo physical deformation to external voltage stimuli. These electrically activated polymers possess extraordinary features making them capable as lightweight sensors and actuators in manifold applications. The characteristics of applied voltage and environmental conditions, especially the moisture content surrounding the polymer, have a combined influence on the dynamical behavior of these polymers. In order to characterize these polymers under varying environmental conditions, this paper discusses the experimental procedure and modeling techniques used to derive a representative model. Ionic polymer metal composite polymers are used for this humidity relative electrodynamical study. Insight on the numerous applications of electroactive polymers as …

High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2004 Through June 30, 2004, Anthony Hechanova

Publications (NSTD)

UNLV hosted a meeting on NHI Materials and Heat Exchanger Design on Monday, May 17. Paul Pickard (Sandia National Lab) and Bill Corwin (Oak Ridge National Lab) facilitated the meeting. The purpose of the meeting was to summarize the hydrogen materials and heat exchanger requirements and priorities for UNLV staff and their collaborators to support the research proposal solicitation for the UNLV Research Foundation HTHX program. Attendance was heavier than anticipated and required a change of venue to accommodate the crowd of over 30.

Optimal Design Of Low Order Controllers Satisfying Sensitivity And Robustness Constraint, Mark L. Nagurka, O. Yaniv

Mechanical Engineering Faculty Research and Publications

The set of all stabilizing controllers of a given low order structure that guarantee specifications on the gain margin, phase margin and a bound on the sensitivity corresponds to a region in n-dimensional space defined by the coefficients of the controllers. For several practical criteria defined in the paper it is shown that the optimal controller lies on the surface of that region. Moreover, it is shown how to reduce that region to avoid actuator saturation during operation.

Spinning Continuous Fibers For Nanotechnology, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

Nanotubes of carbon and other materials are arguably the most fascinating materials playing an important role in nanotechnology today. Their unique mechanical, electronic, and other properties are expected to result in revolutionary new materials and devices. However, these nanomaterials, produced mostly by synthetic bottom-up methods, are discontinuous objects, and this leads to difficulties with their alignment, assembly, and processing into applications. Partly because of this, and despite considerable effort, a viable carbon nanotube–reinforced supernanocomposite is yet to be demonstrated. Advanced continuous fibers produced a revolution in the field of structural materials and composites in the last few decades as a …

The Development Of An Accelerated Testing Facility For The Study Of Deposits In Land-Based Gas Turbine Engines, Jared Wilfred Jensen

Theses and Dissertations

Turbine engine efficiency modeling depends on many parameters related to fluid dynamics and heat transfer. Many of these parameters change dynamically once the engine enters service and begins to experience surface degradation. This thesis presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. It also reports on the use of this facility in an effort to characterize the change in thermal resistance on the surface of turbine blades as deposits accumulate. The facility was designed to produce turbine deposits in a …

Experimental And Numerical Investigation Of Turbulent Flow Induced Pipe Vibration In Fully Developed Flow, Matthew T. Pittard, R. Daniel Maynes, Jonathan D. Blotter, Robert P. Evans

Faculty Publications

Flow-induced pipe vibration caused by fully developed pipe flow has been observed but not fully investigated when turbulent flow prevails. This article presents experimental results that indicate a strong correlation between the volume flow rate and a measure of the pipe vibration. In this work, the standard deviation of the frequency-averaged time-series signal, measured using an accelerometer attached to the pipe, is used as the measure of pipe vibration. A numerical, fluid-structure interaction (FSI) model used to investigate the relationship between pipe wall vibration and the physical characteristics of turbulent flow is also presented. This numerical FSI approach, unlike commercial …

Laser-Assisted Fabrication Of Nmr Resonators, William W. Brey, Susan D. Allen

Mechanical Engineering - Daytona Beach

A detection coil for use in nuclear resonance magnetic (NMR) spectroscopy and a method of manufacture thereof. At least two film layers of material are deposited on an outer surface of a cylindrical tube of dielectric material. The layers are patterned to form a solenoid on the tube. At least one of the deposited materials is a conductor.

Project-Based Introduction To Engineering - A University Core Course, Samuel Bogan Daniels, Bouzid Aliane, Jean Nocito-Gobel, Michael Collura

Engineering and Applied Science Education Faculty Publications

This paper describes a first year engineering course that is taken by both engineering and non-engineering students. The project-based Introduction to Engineering course, EAS107P, fulfills a university core curriculum elective. Although engineering students take the course during their first year, students from other majors typically elect to take the course later in their curriculum. The focus of EAS107P is to have students experience the engineering design and problem solving process in a multi-disciplinary, team-based setting. In addition to learning about design, students develop an interest in the engineering profession and build a foundation of skills for future work. An additional …

Development Of A Multidisciplinary Engineering Foundation Spiral, Samuel Bogan Daniels, Bouzid Aliane, Jean Nocito-Gobel, Michael Collura

Engineering and Applied Science Education Faculty Publications

To operate effectively in today’s workforce engineers need to have a muti-disciplinary perspective along with substantial disciplinary depth. This broad perspective cannot be achieved by merely taking 2 or 3 engineering courses outside of the major, but rather will require a radical change in the way we educate engineers. The faculty of the School of Engineering and Applied Science at the University of New Haven have developed a new approach: the Multidisciplinary Engineering Foundation Spiral. This curricular model provides the needed mix of breadth and depth, along with the desired professional skills, by providing carefully crafted, well-coordinated curricular experiences in …

Project-Based Introduction To Engineering -- Course Assessment, Samuel Bogan Daniels, Michael Collura, Bouzid Aliane, Jean Nocito-Gobel

Engineering and Applied Science Education Faculty Publications

The School of Engineering and Applied Science at the University of New Haven has a newly developed project-based Introduction to Engineering course. This new course plays a central role in the new Multi-Disciplinary Engineering Foundation Spiral curriculum as the first semester course for all engineering freshmen. An assessment process was developed to determine the effectiveness of this project-based course, specifically with attention towards assessing attitudes, impact on retention, problem-solving and engineering foundation topics. This paper addresses the particular portion of the assessment process for the individual course projects and their contribution to the last two assessment categories.

Project Planning & Development For Engineering Freshmen, Bouzid Aliane, Michael Collura, Samuel Bogan Daniels, Jean Nocito-Gobel

Engineering and Applied Science Education Faculty Publications

The nature and background of students seeking an engineering education has changed drastically in the last decade, as has the expectations of industrial employers. Many students lack the organizational skills needed for academic success. Similar organizational skills, although more advanced, are required for managing engineering projects. A new course was developed by the faculty at the School of Engineering and Applied Science at the University of New Haven. Through this course, a key component of the Multidisciplinary Engineering Foundation Spiral, seeks to promote higher retention rates, increase student motivation and begin a confidence-building transition to professional practice. Project management concepts …

Effects Of Friction Stir Processing On The Microstructure And Mechanical Properties Of Fusion Welded 304l Stainless Steel, Colin J. Sterling

Theses and Dissertations

Friction stir processing (FSP) has been utilized to locally process regions of arc weldments in 304L stainless steel to improve the microstructure and mechanical performance. The cast microstructure and coarse delta-ferrite has been replaced with a fine-grained wrought microstructure. Furthermore, twins were introduced throughout the friction stir processed region. Although sub-surface sigma and carbides were introduced during FSP, their presence is not expected to adversely affect the resulting mechanical or corrosion properties of friction stir processed 304L arc welds. The resulting mechanical properties of FS processed weldments were also an improvement over as-welded arc welds. FSP resulted in an increase …

Re-Examination Of “Missing Strain” During Superplastic Deformation Of Aa7475, M. J. Tan, C. L. Chen, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

“Missing strain,” a discrepancy between the total macroscopic strain and the strain contributed by grain boundary sliding (GBS) during superplastic deformation, appears to exist in previous investigations. In this work, the contri¬bution of GBS (ξ_GBS) and intragranular strain (ξ_IG) were simultaneously measured using scratch test conducted on AA7475 samples after deformation at 500 °C at initial strain rate of 10^-3 s^-1. The result shows that the missing strain results most probably from the neglect of the intragranular strain as well as the anisotropic GBS-induced underesti¬mation of ξ_GBS. The calculation of ξ …