Engineering Commons^™

Conjugate Heat Transfer From A Two- Layer Substrate Model Of A Convectively Cooled Circuit Board, S. A. Harman, Kevin D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

This note presents the results of a study of a simple model of an air-cooled electronic device mounted on a circuit board. The model includes a flush-mounted heater to represent the electronic device, a two-layer substrate to represent the circuit board, and a steady shear flow to represent the cooling fluid.

Ortega provides a good review of the literature and a comprehensive introduction to conjugate methods applied to electronic cooling, emphasizing simple shear flows and single-layer substrates to illustrate basic principles. Ortega also describes two-layer effects by including infrared thermographs of a convectively cooled glass/epoxy circuit board with copper traces, …

Meeting The Needs Of Industry: Development Of A Microcontroller Course For Mechanical Engineers, W. G. Culbreth

Mechanical Engineering Faculty Research

No abstract provided.

An Interactive Visual Environment For Scientific Problem Solving, Georg F. Mauer

Mechanical Engineering Faculty Research

No abstract provided.

Linear-Nonequilibrium Thermodynamics Theory For Coupled Heat And Mass Transport, Yaşar Demirel, Stanley I. Sandler

Yaşar Demirel Publications

Linear-nonequilibrium thermodynamics (LNET) has been used to express the entropy generation and dissipation functions representing the true forces and flows for heat and mass transport in a multicomponent fluid. These forces and flows are introduced into the phenomenological equations to formulate the coupling phenomenon between heat and mass flows. The degree of the coupling is also discussed. In the literature such coupling has been formulated incompletely and sometimes in a confusing manner. The reason for this is the lack of a proper combination of LNET theory with the phenomenological theory. The LNET theory involves identifying the conjugated flows and forces …

Languages For Engineering Design: Empirical Constructs For Representing Objects And Articulating Processes, Clive L. Dym, Philip Brey

All HMC Faculty Publications and Research

Design knowledge incorporates knowledge and information about designed objects and their attributes, as well as about methods and means for undertaking the design process. Such design knowledge is articulated in several different representations or languages. This paper presents a typology of the languages of engineering design, emphasizing the representation of designed objects and the articulation and representation of the cognitive processes of design. Design languages include verbal or textual statements, drawings and graphics, formulas, and numbers. Still other design languages follow from computational styles. The languages of design and their computer-based implementations are empirical in origin, since observation reveals that …

Eddy Structures Induced Within A Wedge By A Honing Circular Arc, C. P. Hills

Articles

In this paper we outline an expeditious numerical procedure to calculate the Stokes flow in a corner due to the rotation of a scraping circular boundary. The method is also applicable to other wedge geometries. We employ a collocation technique utilising a basis of eddy (similarity) functions introduced by Moffatt (1964) that allows us to satisfy automatically the governing equations for the streamfunction and all the boundary conditions on the surface of the wedge. The circular honing problem thereby becomes one-dimensional requiring only the satisfaction of conditions on the circular boundary. The advantage of using the Moffatt eddy functions as …

Eddies Induced In Cylindrical Containers By A Rotating End Wall, Christopher Hills

Articles

The flow generated in a viscous liquid contained in a cylindrical geometry by a rotating end wall is considered. Recent numerical and experimental work has established several distinct phases of the motion when fluid inertia plays a significant role. The current paper, however, establishes the nature of the flow in the thus far neglected low Reynolds number regime. Explicitly, by employing biorthogonality relations appropriate to the current geometry, it is shown that a sequence of exponentially decaying eddies extends outward from the rotating end wall. The cellular structure is a manifestation of the dominance of complex eigensolutions to the homogeneous …

Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke

Department of Mechanical and Materials Engineering: Faculty Publications

Task specific uncertainty is the measurement uncertainty associated with the measurement of a specific feature using a specific measurement plan. This paper surveys techniques developed to model and estimate task specific uncertainty for coordinate measuring systems, primarily coordinate measuring machines using contacting probes. Sources of uncertainty are also reviewed.

On Modular Design Of Field Robotic Systems, Shane Farritor, Steven Dubowsky

Department of Mechanical and Materials Engineering: Faculty Publications

Robots are needed to perform important field tasks such as hazardous material clean-up, nuclear site inspection, and space exploration. Unfortunately their use is not widespread due to their long development times and high costs. To make them practical, a modular design approach is proposed. Prefabricated modules are rapidly assembled to give a low-cost system for a specific task. This paper described the modular design problem for field robots and the application of a hierarchical selection process to solve this problem. Theoretical analysis and an example case study are presented. The theoretical analysis of the modular design problem revealed the large …

Bicycle Braking System, Noel Brady

Patents

A bicycle braking system for permitting controlled rotation and continuous power to the wheels of a bicycle during braking of the bicycle to enhance control of the bicycle during braking includes a cylindrical brake pad that is spring loaded within angled slots in a casing. The brake pad is positioned proximate the rim of a wheel and a cable assembly is coupled to the brake pad for urging the brake pad towards an end of the angled slots and against the rim of the wheel to slow rotation of the wheel.

Using A Rapid Prototyping Machine In The Integrated Kinematics, Dynamics, And Machine Design Lab, Wieslaw M. Szydlowski

Department of Mechanical and Materials Engineering: Faculty Publications

According to a recent trend, two different labs - the Machine Design lab, and Kinematics, and Dynamics lab are combined into one integrated lab. The time students spend on their projects is halved. To save the quality of undergraduate education, an ew methodology has to be developed. The paper explains the methodology developed by the author while teaching the integrated Kinematics, Dynamics, and Machine Design Lab (MECH 488) at the Mechanical Engineering Department of the University of Nebraska-Lincoln.

The objective of the aforementioned lab is to teach the students, who have no design experience, how to select proper tools (firom …

Optimization Of A Multi-Aixs Electro-Mechanical Scanning System., Raul Urbina

Electronic Theses and Dissertations

This thesis presents efforts to enhance the system performance of an ultrasonic scanning machine. New developments in electronics are used to enhance the system performance. This work focuses on optimizing the system repeatability with a robust triggering system for the scanner. The robust triggering system applies new advances in programmable logic devices that make the replacement of complicated digital circuits possible. Modeling of wave propagation through anisotropic media is used to increase the system dynamic range. The model-based gain control compensates for variations in thickness and materials by controlling the excitation pulse amplitude. The automatic gain is implemented using integrated …

The Flexural Response Of Bolted Composite Panels At Elevated Temperature, Christopher Gary Malm

Electronic Theses and Dissertations

Carbon fiberlcyanate ester matrix composite panels with bolted connections to aluminum endplates were tested in four point bending at room and elevated temperatures. The specimens tested were subcomponents of the NASA X-38 Crew Return Vehicle. The X-38 is the proposed escape vehicle for the International Space Station, currently being constructed in Earth orbit. During reentry into the Earth's atmosphere, the composite aeroshell of the X-38 is expected to experience elevated temperatures, which makes accurate characterization of material properties at elevated temperature imperative to a sound design. Three varieties of specimens were tested: flat composite laminates, hat-stiffened composite laminates, and sandwich …

To Research, Analyse And Install An Optimised Maintenance Management System For A Medium Sized Manufacturing Company: A Textile Company Case Study, Christopher O'Donoghue

Theses

Modern manufacturing is continually striving to ensure that products are made to higher levels of quality with faster lead times and at the lowest possible costs. Manufacturing production has never been more reliant on machines and automated processes than it is today. This thesis investigates the management philosophies that are in existence, which cater specifically for maintenance and maintenance related issues. Management philosophies such as Reliability Centred Maintenance (RCM), Total Productive Maintenance (TPM), Profit Centred Maintenance (PCM), asset management (AM), Predictive Maintenance (PdM), Condition Based Maintenance (CBM) and World Class Maintenance (WCM) have increased company profits by drastically reducing maintenance …

Mathematical Modeling For Fabricating A Microstructure With A Pre-Specified Geometry Using Laser -Induced Chemical Vapor Deposition, Chaoyang Zhang

Doctoral Dissertations

Laser-induced chemical vapor deposition (LCVD) is an emerging new technique with many practical applications. To optimize the system for fabricating a microstructure with a pre-specified geometry in pyrolytic LCVD, a three-dimensional mathematical model is developed for predicting temperature distributions and laser dwell times across the substrate scanned by the laser beam. A microstructure is fabricated layer by layer, and for each layer the laser beam moves from one pixel to the next. The complicated correlations among temperature distribution, deposit growth rate, and laser dwell time are investigated. A purely heterogeneous reaction is assumed and any gas-phase transport is ignored.

A …

Microstructure-Sensitive Design Of A Compliant Beam, Brent L. Adams, Alisa J. Millar Henrie, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi

Faculty Publications

BA acknowledges financial support provided by the MRSEC Program of the National Science Foundation under Award Number DMR-9632556. SK acknowledges financial support from National Science Foundation under Award Number CMS-9732699. BA, SK and HG also acknowledge support from the NSF-CIRE program centered at Florida A&M University, facilitating collaborations. Support was also provided by the College of Engineering and Technology at BYU (AH, BH and ML). Computations were performed on the new SGI Origin 2000 supercomputer at Brigham Young University, donated by Ira Fulton. We show that mechanical design can be conducted where consideration of polycrystalline microstructure as a continuous design …

Nebraska Summary 354: Agco Dt200 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 355: Agco Dt225 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1789: John Deere 9200 24 & 12 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 388: Fendt 918 Vario Diesel, 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 1791: John Deere 9400t Also 9420t 24 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 391: Fendt 926 Vario Diesel, 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 1796: Case Ih Stx 275/New Holland Tj 275 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1797: Case Ih Stx 325/New Holland Tj 325 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1790: 9300 T 24 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1796: Case Ih Stx 275/New Holland Tj 275 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1797: Case Ih Stx 325/New Holland Tj 325 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1792: Massey Ferguson 2210 Diesel 15-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 1793: Massey Ferguson 2220 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 …

Nebraska Summary 389: Fendt 920 Vario Diesel, 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 …