Mechanical Engineering Commons^™

Progress Toward Meeting The Challenges Of Our Coastal Urban Future, Juile Pullen, Jason Ching, David J. Sailor, William Thompson, Bob Bornstein, Darko Koracin

Mechanical and Materials Engineering Faculty Publications and Presentations

The article provides information on the Seventh Conference on Coastal Atmospheric and Oceanic Prediction and Processes, and the Seventh Symposium on the Urban Environment in San Diego, California on September 9-13, 2008. Topics include the heterogeneity of urban areas, coastal vulnerabilities, urban planning, and emergency response modeling. The conference featured several speakers including Walter Dabberdt and James Voogt.

Using Building Energy Simulation And Geospatial Modeling Techniques In Determine High Resolution Building Sector Energy Consumption Profiles, Shem C. Heiple

Dissertations and Theses

A technique is presented for estimating hourly and seasonal energy consumption profiles in the building sector at spatial scales down to the individual taxlot or parcel. The method combines annual building energy simulations for cityspecific prototypical buildings and commonly available geospatial data in a Geographical Information System (GIS) framework. Hourly results can be extracted for any day and exported as a raster output at spatial scales as fine as an individual parcel (

Capillary Flow Analysis And Computation Of De-Wetting And Wetting Resistances In Angular Geometries, Daniel Bolleddula

Dissertations and Theses

Capillary flows in containers or conduits with interior corners are commonplace in nature and industry. The majority of investigations addressing such flows solve the problem numerically in terms of a flow resistance coefficient (friction factor) for cases where spontaneous liquid spreading along the corner occurs for contact angles below the Concus-Finn critical wetting condition for the particular conduit geometry of interest. This research effort provides missing numerical data for the flow resistance function F_i for partially wetting systems above the Concus-Finn condition. In such cases the fluid spontaneously de-wets the interior corner and often retracts into corner-bound drops. A …

Dynamic Characterization Of Aluminum Softball Bats, Danny V. Lee

Dissertations and Theses

On January 1, 2000, the Amateur Softball Association of America (ASA) imposed maximum bat performance limitations on commercial softball bats. The ASA adopted a testing standard defined by the American Society of Testing and Materials (ASTM) to determine the bat performance factor (BPF), a normalized coefficient of restitution that must be less than 1.2 for the bat to be eligible for ASA sanctioned events.

The ASTM standard requires that the softball strike the bat, which is free to rotate in the horizontal plane, at 26.8 mfs ± 0.3 mfs (88 ftfs ± 1 ftfs) with little or no spin. The …

Communicating Conceptual Design Of Mechatronic Systems, Muir Lee Harding

Dissertations and Theses

Today's engineering designers must adapt to a changing model of product development. In the past, a single engineer could design, develop and deploy competitive systems --this is often no longer the case. Designing a mechanical system with integrated microprocessor control requires the collaboration of a cross-disciplinary team of engineers and, in many cases, no single member of the team understands the workings of the entire system. Consequently, as systems become increasingly complex, the ability to collaborate and reliably communicate design information becomes more and more crucial. Effective communication 1s particularly critical in conceptual design, where a poor decision has the …

Limitations Of Methods For Determining The Position Of The Center Of Mass Of A Human Subject Performing A Sit-Up, Terrence Chadwick Smith

Dissertations and Theses

The knowledge of the position of the center of mass of a human subject performing a sit-up could help us understand the coordination of the sit-up motion. This thesis investigates the limits in three methods of determining the center of mass of a human subject. The three methods are the anthropometric method, the dynamic method, and the static torque method. The anthropometric method is a standard method that uses measurements of the subject to estimate the mass properties of individual segments of the body. The center of mass of the body is calculated from the mass and positions of the …

Tool Condition Monitoring: A Computational Approach, Anthony Clinch

Dissertations and Theses

Tool Condition Monitoring offers a new approach to reducing the costs associated with catastrophic tool failure. The manufacturing process is becoming more computationally oriented all the time. Computational methods of determining the condition of cutting tools will lend themselves to easy integration with current and forthcoming manufacturing techniques. Coupling the results of this computational approach with a cost analysis will provide a means of maximizing the investment in cutting tools, while minimizing the damage caused by tool failure. Tool Condition Monitoring, as defined here, is a method of computationally determining the condition of a cutting tool. The problem of determining …

Malt Drying Model Verification For Efficiency Improvement, John David Kribs

Dissertations and Theses

The aim of this work has been to minimize the thermal energy required to dry malt in deep beds while maintaining malt quality, and without increasing the drying time more than one hour. Malt drying usually takes place in deep bed (. 7-1 m) driers by forcing hot air through the bed. Measurements of inlet and outlet relative humidity, temperature, and airflow at a drier at Great Western Malting Company's Vancouver, Washington facility were made to find average moisture content versus time. The measurements were used to develop a wetted surface model of a malt bed. However, the model was …

Quasi-Static Deflection Compensation Control Of Flexible Manipulator, Jingbin Feng

Dissertations and Theses

The growing need in industrial applications of high-performance robots has led to designs of lightweight robot arms. However the light-weight robot arm introduces accuracy and vibration problems. The classical robot design and control method based on the rigid body assumption is no longer satisfactory for the light-weight manipulators. The effects of flexibility of light-weight manipulators have been an active research area in recent years. A new approach to correct the quasi-static position and orientation error of the end-effector of a manipulator with flexible links is studied in this project. In this approach, strain gages are used to monitor the elastic …

Effectiveness Of Additive Correction Multigrid In Numerical Heat Transfer Analysis When Implemented On An Intel Ipsc2, James D. Padgett

Dissertations and Theses

The effectiveness of the Additive Correction Multigrid (ACM) algorithm, a line-byline Tri-diagonal Matrix Algorithm (TDMA), and simple Gauss-Seidel (GS) iteration in numerical heat transfer analysis is investigated on a conventional single processor computer and on a distributed memory parallel computer. The performance of these methods is studied by solving a two-dimensional, steady heat conduction problem. The execution time of ACM on a single processor is proportional to the number of unknowns to the 1.5 power. This is in contrast to the execution time of the TDMA for which the execution time is proportional to the number of unknowns to the …

Hypoid Gear Optimization, Selvaraj Ramachandran

Dissertations and Theses

A hypoid gear optimization procedure using the method of feasible directions has been developed. The objective is to reduce the gear set weight with bending strength, contact strength and facewidth-diametral pitch ratio as constraints. The objective function weight, is calculated from the geometric approximation of the volume of the gear and pinion. The design variables selected are number of gear teeth, diametral pitch, and facewidth. The input parameters for starting the initial design phase are power to be transmitted, speed, gear ratio, type of application, mounting condition, type of loading, and the material to be used. In the initial design …

Development Of An Advisory System For Indoor Radon Mitigation, Patricia Hiromi Byrne

Dissertations and Theses

A prototype hybrid knowledge-based advisory system for indoor radon mitigation has been developed to assist Pacific Northwest mitigators in the selection and design of mitigation systems for existing homes. The advisory system employs a heuristic inferencing strategy to determine which mitigation techniques are applicable, and applies procedural methods to perform the fan selection and cost estimation for particular techniques. The rule base has been developed employing knowledge in existing publications on radon mitigation. Additional knowledge has been provided by field experts. The benefits of such an advisory system include uniform record-keeping and consistent computations for the user, and verification of …

Decomposition Of Measured Contours Into Geometric Features For Dimensional Inspection, Devaraj Rajkumar

Dissertations and Theses

Image processing systems used in Vision Assisted Dimensional Inspection usually output a set of boundary pixels representing the part edges. This boundary information must be divided into several subsets representing the various edges of the actual object, so that comparisons with the nominal part can be made.

The purpose of this project is to devise a method to divide the set of pixels obtained from the image processing system into subsets of pixels. Each of these subsets represent an edge in the contour of the actual object. This method must also detect transition points between the adjacent features. This project …

Finite Element Analysis Of Thermal Stresses In Semiconductor Devices, Joachim Karl Wilhelm Duerr

Dissertations and Theses

The failure of integrated circuit due to Silicon fracture is one of the problems associated with the production of a semiconductor device. The thermal stresses, which result in die cracking, are for the most part induced during the cooling process after attaching the die with Gold-Silicon solder. Major factors for stress generation in material systems are commonly large temperature gradients and substantial difference in coefficients of thermal expansion.

This research covers the thermal stresses introduced upon cooling a composite Silicon device. A transient thermal analysis has been performed to determine the temperature gradients. The stress distribution has been investigated. For …

A Comparative Study Of The Performance Of Various Image Analysis Methods For Dimensional Inspection With Vision Systems, Ralf Heinrich Koeppe

Dissertations and Theses

Dimensional inspection with Vision Systems requires a careful selection of image analysis methods in order to obtain accurate information about the geometry of the parts to be measured.

The purpose of this project is to study, implement and compare different image evaluation methods and to show their strengths and weaknesses with respect to dimensional inspection. Emphasis is made on the inspection of circular features. The criteria of comparison for these methods are discussed. Using synthetically generated images, various analysis methods are compared and conclusions for their use are drawn. Results of the comparison show that the selection of a method …

Development Of A Parametric Analysis Microcomputer Model For Evaluating The Thermodynamic Performance Of A Reciprocating Brayton Cycle Engine, Thomas Joseph White

Dissertations and Theses

In this thesis, applicable data from research on IC engines have been adapted to PACE engine designs. Data from studies on heat transfer, friction, and pressure losses, in particular, have been used. Certain parameters which define operation and design characteristics appear to influence PACE engine performance very strongly. Some of the more critical parameters, notably friction and heat transfer coefficients, must be determined experimentally if accurate model results are to be expected. Pressure ratio, compressor RPM, and maximum combustor temperature, the independent operating parameters, also have a dramatic effect on engine performance. Other design or operating characteristics and working fluid …

The Mechanics Of Flycasting: The Flyline, Graig A. Spolek

Mechanical and Materials Engineering Faculty Publications and Presentations

In order to propel a fishing fly through the air toward the distant quarry, a rather massive line, to which the fly is attached, is cast. As the cast line rolls out, the fly actually accelerates horizontally and seems to defy physical law. The phenomenon is modeled simplistically to determine the magnitude of this effect. In the absence of air drag, the fly can accelerate to increase its velocity by an order of magnitude. Air friction dramatically decreases the effect, but some fly accelerationis still predicted. By tapering the flyline in various ways, the fly velocity history can be significantly …

Post-Buckled Performance Of Partially Restrained And Intermediately Supported Steel Angles, Perumal Radhakrishnan

Dissertations and Theses

The post-buckled performance of cross-braced single angles was experimentally determined. The results of this study will be used by the Bonneville Power Administration for the analysis of member performance in transmission towers.

Transient Flow Inverse Study Calculation Of Unsaturated Permeability Of Wood, Farid Piroozmandi

Dissertations and Theses

One of the major processes in lumber industry is wood drying. This process consumes large amounts of energy and capital, and due to the length of time it takes, it acts as a governing factor in lumber production levels. Development of improvements in processes and equipment used in wood drying can be expedited through computer simulation of various drying procedures. These numerical simulations depend on the accuracy of numerical models representing wood transport properties, including functional dependency of liquid permeability through wood with respect to local saturation level. Data available in the literature mainly represent wood permeability properties at fully …

Determination Of Systemic Blood Pressure Via Autospectral Analysis Of Oscillometric Data, Eugene Elie Warner

Dissertations and Theses

The currently accepted methods for measuring systemic blood pressure are either highly accurate but invasive in nature or clinically convenient but prone to observer-related errors. A new oscillometric method uses sensitive signal conditioning and sensing equipment with a non-invasive arm cuff to record arterial pulsations. The goal of this study is to establish more reliable criteria for the identification of systolic and diastolic pressures from oscillometric data.

Liquid Transmission Line Pulser Circuit For Laser Excitation, Carl Stultz

Dissertations and Theses

The subject of this thesis is the study of liquid dielectric transmission lines and their potential application as an excitation source in high speed, high-repetition rate laser designs. The design problems associated with the construction of high repetition rate (khz), short wavelength lasers have been reviewed and the major shortcomings of conventional electrical driving circuits identified. The identification of these shortcomings and a review of the available literature on electrical circuits for various types of lasers suggested that liquid dielectrics and transmission lines could potentially have significant advantages over more conventional circuitry used in high repetition rate, short wavelength lasers. …

Investigation Of Blood Pressure Measurement Using A Hydraulic Occlusive Cuff, Kusha R. Bhattarai

Dissertations and Theses

This thesis presents an improved oscillotonometric system for the measurement of human blood pressure. The study included:

1. The design of a hydraulic occlusive cuff,

2. The investigation of the wave forms taken from the blood pressure measurements, and

3. The design of a mechanism for the simulation of human blood pressure pulse.

In this study, an experimental system consisting of a rigid shell occlusive cuff, a constant volume displacement pump, a transducer, and a chart recorder was designed and used for data collection.

Experimental Determination Of Post-Buckling Performance Of Steel Angles, Rupasiri Purasinghe

Dissertations and Theses

An experimental testing program was conducted to determine the compression member performance in post-buckling region. These results are compared with an analytical computer program developed by Portland State University under Bonneville Power Administration Contract 79-80BP 24005. The paper presents the sensitivity of the performance of single angle compression members to various parameters such as length to radius of gyration ratio, eccentricity, end conditions and yield stress. The effect of local buckling on long member performance is also documented.

Reduction Of Capacitor Switching Transients By Controlled Closing, John Herman Brunke

Dissertations and Theses

This thesis presents the theory, analysis, testing and implementation of a scheme to reduce shunt compensation capacitor switching transients. The described method is switch the capacitors very near the instant when the bus voltage is at a power frequency zero. This was accomplished with a vacuum breaker on a 230 kV shunt capacitor bank.

Computer Aided Optimal Design Of Helical Gears, S. N. Muthukrishnan

Dissertations and Theses

A random search method for optimum design of a pair of helical gears has been developed. The sequence of optimization consists of two principal components. The first is the selection phase, where the output is the starting solution for the design variables - module, facewidth, helix angle and number of teeth on the pinion. The input for the selection phase includes the application environment, approximate center distance, minimum helix angle, desired values of gear ratio, pinion speed and the power to be transmitted. The limits on each of the design variables and the constraints are imposed interactively during the first …

The Design And Construction Of A Flashlamp-Pumped Frequency-Doubled Dye Laser Applicable To Long Path Monitoring Of Air Pollutants, Joel Craig Johnson

Dissertations and Theses

The subject of this thesis is the development of a laser light source which could be used in an air pollution monitor to measure the average concentration of sulfur dioxide gas over long paths (>1 km). Many of the problems encountered in designing a long-path pollutant monitor such as instrument cost and reliability, the selection of an optimum spectral region for making the measurement, and light losses due to scattering and turbulence, are considered. The result of these considerations together with a survey of available laser light sources suggested that a frequency-doubled dye laser possessed several advantages over other …

The Development And Testing Of A Fluidic/Pneumatic Position Servo, David Lyle Portin

Dissertations and Theses

This thesis reviews the design and analysis of a fluidic/pneumatic position servo. Rolling diaphragm piston actuators are used for the system drive, and a hydrostatic gas journal bearing is used as the position sensor. The servo has a 1 inch range which is monitored using an electrical capacitive position transducer that was built as an integral part of the system.

Open-loop frequency response testing provides the basis for a mathematical model of the system.

The servo response is linear at frequencies up to 3 Hertz.

The frequency response appeared to be limited by the design of the gas bearing sensor, …

The Analysis Of The Deflection And Containment Of A Hot Plume By Side Draft Exhaust Hooding, Douglas H. Macgowan

Dissertations and Theses

A common industrial ventilation and pollution problem results when a thermally buoyant polluted plume of air must be exhausted away from a work area to allow achievement of air pollution standards. Generally, a close fitting canopy hood is one of the most effective means of exhaust containment; however, physical restrictions or the operation itself often prevent such an arrangement, and a hood located to the side of the operation is required. This arrangement requires the exhaust to bend and contain the vertically rising plume with a horizontal sweep of exhaust air across the surface of the operation.

A review of …

Computer Solution To Inverse Problems Of Elliptic Form: V²U(X,Y) = G(A,U,X,Y), Frederick Alvin Jeter

Dissertations and Theses

One important aspect of our present age of monolithic high speed computers is the computer's capability to solve complex problems hitherto impossible to tackle due to their complexity. This paper explains how to use a. digital computer to solve a specific type of problem; specifically, to find the inverse solution of a in the elliptical equation V²U(x,y) = g(a,U,x,y), with appropriate boundary conditions. This equation is very useful in the electronics field. The knowns are the complete set of boundary values of U(x,y) and a set of observations taken on internal points of U(x,y). Given this information, plus …

Direct Design Of A Portal Frame, Angel Fajardo Ugaz

Dissertations and Theses

This investigation was undertaken to develop plastic design aids to be used in the direct design of optimum frames. It uses the concept of minimum weight of plastically designed steel frames, and the concept of linear programming to obtain general solutions. Among the special characteristics of this study are: A. The integration of both gravity and combined loading conditions into one linear programming problem. B. The application of the revised simplex method to the dual of a parametric original problem. C. The application of A and B above in the development of design aids for the optimum design of symmetrical …