Engineering Commons^™

Shock Layer Instability Near The Newtonian Limit Of Hypervelocity Flows, H. G. Hornung, P. Lemieux

Mechanical Engineering

The curved bow shock in hypersonic flow over a blunt body generates a shear layer with smoothly distributed vorticity. The vorticity magnitude is approximately proportional to the density ratio across the shock, which may be very large in hypervelocity flow, making the shear layer unstable. A computational study of the instability reveals that two distinct nonlinear growth mechanisms occur in such flows: First, the vortical structures formed in the layer move supersonically with respect to the flow beneath them and form shock waves that reflect from the body and reinforce the structures. Second, the structures deform the bow shock, forming …

Removing Barriers To High-Strength Concrete In Boston, Daniel C. Jansen, Herman Protze

Civil and Environmental Engineering

No abstract provided.

Microwave Modulation Of A Quantum-Well Laser With And Without External Optical Injection, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

We compare three microwave modulation methods experimentally and theoretically using a semiconductor quantum-well (QW) Fabry–Perot test laser: 1) direct microwave current modulation of the test laser (electrical modulation); 2) optical modulation by an external single-wavelength pump laser with a modulated optical injection power; and 3) electrical modulation of the test laser that is injection locked by an external single-wavelength pump laser with a constant injection power. This is the first direct comparison of the three modulation methods on the same QW laser, to the best of our knowledge. The bandwidth of optical absorption modulation is 7.7 GHz, which is 1.45 …

Asee Student Chapters: From Student Members To Faculty, Jennifer Kadlowec, Kurt Degoede, Trevor S. Harding, Christian Lorenz

Materials Engineering

The University of Michigan Student Chapter of the American Society for Engineering Education has grown from a small core group of founding members, who organized panel discussions for the graduate student community, into a flourishing student organization, which continues to grow in membership and events. The purpose of this paper is to promote graduate student chapters of the ASEE and demonstrate the positive impact that student member participation has had, particularly for those who have recently entered academia. Many events and activities of the University of Michigan Student Chapter of the American Society for Engineering Education (UM-ASEE Student Chapter) will …

The Foundation Series On Corrosion: Integrating Science, Math, Engineering & Technology In A Lab Setting, Linda Vanasupa, Heather Smith, Blair London, Katherine C. Chen, David Niebuhr, Lanny Griffin, Jeff Jones

Materials Engineering

We have developed a laboratory module focusing on the subject of corrosion. The module itself is designed to be completed in one three-hour session. It consists of three parts: I. The Impact of Corrosion Media, II. The Impact of Corroding Materials, III. The Impact of Anode/Cathode Sizes. Our objectives in developing this module were to address the need for clear bridges between math, science and technology in the engineering curriculum and to provide a means of faculty development primarily at community colleges. As a result, it was designed to allow the engineering student to experience the synergy of science, math …

Useful Approaches To Preventing Academic Dishonesty In The Classroom, Trevor S. Harding

Materials Engineering

Over the past three decades, academic dishonesty (a.k.a. cheating) has become an increasingly common occurrence among college-aged students, and engineering students are known to be among the most frequent culprits. At most universities, cheating is dealt with after the fact. Few institutions go beyond drafting an academic integrity policy to prevent cheating before it happens. The same situation exists in the classroom. The majority of college professors report doing little or nothing to reduce the frequency of cheating in their classes, usually because of a lack of awareness of its occurrence. And when cheating is observed, faculty overwhelmingly choose to …

On The Frequency And Causes Of Academic Dishonesty Among Engineering Students, Trevor S. Harding

Materials Engineering

According to studies of self-reported academic dishonesty conducted over time, cheating among college students has been on the increase since at least the 1940’s. This is especially true for engineering students who are now among the most likely to cheat compared to other disciplines. This paper will present a synopsis of the literature on academic dishonesty. In addition, the results of a pilot study on cheating among engineering students conducted at a small mid-western private engineering school are described. Engineering students in an introductory engineering materials course were asked to complete a survey on their perceptions of cheating; therefore, all …

Greasing The Tenure Track 2, David Braun

Electrical Engineering

Some new faculty must balance the competing demands of the desire to teach effectively while maintaining a heavy teaching load. Oh, and, by the way, along the way to the tenure hurdle, research, professional development, and service duties may distract from family, friends, and real life. Based on the author’s participation in the NSF's New Century Scholars (NCS) Workshop at Stanford University as both a scholar (1999) and, subsequently, as a senior scholar (2000), this paper summarizes six useful tips for tenure-track faculty. This second paper in the series by NCS senior scholars provides the perspective of an engineering educator …

Computer-Aided Engineering For Tool Design In Manufacturing Engineering Curriculum, Daniel J. Waldorf

Industrial and Manufacturing Engineering

At Cal Poly – San Luis Obispo, a variety of tool design issues are covered in a junior-level manufacturing engineering course called Tool Engineering. In the course, designing fixtures – for any process – is a major component of the content. The process of designing a fixture is similar to the method a mechanical engineer would use to design a new product. The course is therefore an excellent opportunity to teach design principles to manufacturing engineers. This project involves an attempt to introduce computer-aided methods, including the finite element method (FEM), for analysis of tool design into the Tool Engineering …

Using Lip Features For Multimodal Speaker Verification, Xiaozheng Zhang, Charles C. Broun

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics is viewed as an essential component of current and evolving technological systems. Consumers demand unobtrusive and non-invasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

We propose a multimodal approach that builds on our current state-of-the-art speaker verification technology. In order to maintain the transparent nature of the speech …

Plasma Deposition Of Spin Chucks To Reduce Contamination Of Silicon Wafers, Richard N. Savage, Emir Gurer, Ed C. Lee

Materials Engineering

An apparatus for delivering a fluidic media to a wafer includes a housing defining a process chamber. A fluidic media delivery member is coupled to the process chamber. A rotatable chuck is positioned in the process chamber. The rotatable chuck has a wafer support surface coated with a coating material. A vacuum supply line is coupled to the rotatable chuck.

Teaching Factory, Sema E. Alptekin, Reza Pouraghabagher, Patricia Mcquaid, Daniel Waldorf

Industrial and Manufacturing Engineering

Academia must develop a new approach to teaching in order to better prepare engineering students to function efficiently and adjust readily within the framework of the factories in the real world. Some engineering programs emphasize theory, while others emphasize application as isolated blocks. The "Teaching Factory" being developed at Cal Poly combines both theory and applications. It makes use of state-of-the-art industrial grade production equipment, computer hardware and software in the form of the following two systems: 1) a functioning "real" factory hardware environment, and 2) a Production Planning and Control Center.

The Role Of The Journal In Mentoring Students, Harold M. Cota

Civil and Environmental Engineering

No abstract provided.

The Effect Of Reliability Consideration On The Application Of Quality Index, Hamid Seifoddini, Manocher Djassemi

Industrial Technology and Packaging

Quality index (QI) has been proposed as a screening mechanism for machine-part matrices in the development of cellular manufacturing systems. In this paper the effect of reliability consideration on the application of QI and the relative sensitivity of job shop and cellular manufacturing systems to reliability changes are evaluated by simulation modeling. Performance measures such as mean flow time and work-in-process inventories are used in the comparative study of job shop and cellular manufacturing.

Determination Of Statistical Characteristics Of Isotropic Turbulence, Tatiana A. Andreeva, William W. Durgin, F. J. Weber, Hamid Johari

Office of the Provost Scholarship

Ultrasonic flow measurement technology has the potential to significantly improve flow measurement accuracy beyond that presently achieved. However, current applications fail to achieve theoretical accuracies because of turbulence effects on ultrasonic wave transit time. Herein, the ultrasonic flowmeter equation is reconsidered, where the effects of turbulent velocity and sound speed fluctuations are included. The result is an integral equation for the corresponding correlation functions. In this paper experimental velocity data are used to solve this integral equation analytically. As a result, some statistical characteristics of the turbulent flow are developed and can explain the limitations of measurement accuracy observed in …

Ultrasonic Beam Propagation In Turbulent Flow, William W. Durgin, F. J. Weber, Hamid Johari

Office of the Provost Scholarship

A study was conducted to examine how a coherent sound burst, such as those used in an ultrasonic flowmeter, crosses a turbulent flow field. Many ultrasonic flowmeters use a time of flight method to determine the mean flow. This measurement method sends sound waves at some angle across a velocity field between two transducers, and the time required for the sound burst to cross this distance is measured on the order of nanoseconds. The system then reverses so that the sound wave burst is sent in the opposite direction. Knowing the distance traveled, the local average sound speed, and the …

Ultrasonic Assessment Of Stabilized Soils, Nazli Yesiller, James L. Hanson, Mumtaz A. Usmen

Civil and Environmental Engineering

The feasibility of using ultrasonic testing, in particular P-wave velocities, to evaluate stabilized soils was investigated. A high-plasticity clay soil that was stabilized with lime, cement, and lime - fly ash mixtures was used in the study. The testing program consisted of determination of P-wave velocities and compression characteristics of the stabilized soils immediately after compaction and subsequent to 7 days and 28 days of curing. Variation of velocity with stabilizing agent, curing time, and also with the compression characteristics of the soils was investigated. It was observed that P-wave velocities were higher for samples stabilized with cement compared with …

Stress-Temperature Effects On Peat Compression, James L. Hanson, Tuncer B. Edil, Patrick J. Fox

Civil and Environmental Engineering

Laboratory and field tests have shown that accelerated compression of peat soils occurs in response to moderate heating and an effective overconsolidation is produced on subsequent cooling. This phenomenon has been termed thermal precompression. In this study, long-term laboratory and field tests were conducted to investigate secondary compression behavior of peat as a function of stress and temperature. Stepstress and step-temperature compression tests were conducted on two peat soils. Dramatic effects were observed upon heating and cooling. A field test site in Middleton, Wisconsin, USA was constructed to test the thermal precompression concept for in situ peats. The site contained …

Improved Direct Displacement-Based Design Procedure For Performance-Based Seismic Design Of Structures, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

Direct displacement-based design requires a simplified procedure to estimate the seismic deformation of an inelastic SDF system, representing the first (elastic) mode of vibration of the structure. This step is usually accomplished by analysis of an “equivalent” linear system using elastic design spectra. In this paper, an equally simple procedure is developed that is based on the well-known concepts of inelastic design spectra. This procedure provides: (1) accurate values of displacement and ductility demands, and (2) a structural design that satisfies the design criteria for allowable plastic rotation. In contrast, the existing procedure using elastic design spectra for equivalent linear …

Using Genetic Algorithms And Swat To Minimize Sediment Yield From An Agriculturally Dominated Watershed, Misgana K. Muleta, John W. Nicklow

Civil and Environmental Engineering

Non-point source pollution is well recognized as one of the most critical environmental hazards of modern times. In Illinois, non-point source pollution is the major cause of water quality problems, and soil erosion from agricultural lands is the major source of such pollution. Accelerated by anthropogenic activities, soil erosion reduces crop productivity and leads to subsequent problems from deposition on farmlands and in water bodies. Watershed management, however, promotes protection and restoration of these natural resources while allowing for sustainable economic growth and development. In this study a discrete time optimal control methodology and computational model are developed for determining …

Heat Treatment Of Gamma Titanium Aluminide Alloys, Thomas J. Kelly, Michael J. Weimer, Curtiss M. Austin, Blair London, Donald E. Larson Jr., Dean A. Wheeler

Materials Engineering

A gamma titanium aluminide alloy article, is prepared using a piece of a gamma titanium aluminide alloy having a composition capable of forming alpha, alpha-2, and gamma phases. The alpha transus temperature of the gamma titanium aluminide alloy piece is determined. The gamma titanium aluminide alloy piece is consolidated by hot isostatic pressing at a temperature of from about 50 F. to about 250 F. below the alpha transus temperature and at a pressure of from about 10,000 to about 30,000 pounds per square inch, for a duration of from about 1 to about 20 hours. The piece is heat …

Effects Of Filament Reinforced Plexiglass Pressure Vessel On Failure Analysis, Faysal A. Kolkailah, Eltahry Elghandour, Luis J. Valenzuela

Aerospace Engineering

This paper presents an investigation into the effect of reinforcing a Plexiglas tube with fiberglass/epoxy threads wound at different angles. This paper shows an experimental analysis approach to find the ultimate failure pressure of these vessels. The properties of the Plexiglas, fiberglass, orientation (wind) angle and the matrix were taken into account to determine their effects on the ultimate failure pressure of the vessels. Mandrels were wound at +/- 75, +/- 65, and +/- 55 deg, and specimen were cut out from each to 19.05 cm long, 7.62 cm inner diameter and outer diameters dependent of the wind angle. The …

The Study Of Empirical Methodology To Observe Damping Characteristics Of Various Laminate Composite Plates, Faysal A. Kolkailah, Eltahry Elghandour, Taikha Oh, Jason Bolosan

Aerospace Engineering

Modifying the stiffness of the structure is usually not a feasible solution to enhancing damping, since changing the stiffiless effects the natural frequency changing and eventually the condition of resonance will be reached. Therefore, one of the recommendatory ways to reduce the response on structural elements is to improve damping characteristics. The objectives of this study are to present empirical methodology to detect damping characteristics of structural elements, and determine the optimal location of sensor to detect structural failure by analyzed data from both experimental and numerical analysis. Using orthotropic composite plates comprised of 977-2 Carbon fiber/IM7 epoxy, the natural …

7v Tristate-Capable Output Buffer Implemented In Standard 2.5v Cmos Process, Vladimir I. Prodanov, Vito Boccuzzi

Electrical Engineering

This paper describes high-voltage CMOS buffer architecture that uses low-voltage transistors. The voltage capability of the presented architecture is nearly three times larger than the voltage capability of the used MOSFET's. This buffer topology could be used to provide 3.3 V compatibility of 1.2 V and 1.5 V digital ICs implemented in standard CMOS technology. A 7 V circuit-prototype was fabricated in 0.25 /spl μ/m 2.5 V CMOS technology. Performed measurements demonstrate stress-free operationin both active and high-impedance mode.

Robust High-Pass And Notch Gm - (Grounded) C Biquads: How Many Different Topologies Are There?, Vladimir I. Prodanov

Electrical Engineering

This paper deals with Gm-C biquadratic filters that use grounded capacitors. We derive all practical HP and notch filter topologies that do not require critical component matching. The aim of this derivation was to discover new architectures. The result of this derivation is quite unexpected: there are only three distinct topologies (one notch and: two high-pass). None of them is particularly new because all reported in the literature biquad circuits are their embodiments.

Measurement Of Linewidth Enhancement Factor Of Semiconductor Lasers Using An Injection-Locking Technique, G. Liu, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

A new method for measuring the linewidth enhancement factor of semiconductor lasers using the injection-locking technique is presented. This idea is based on the relation between the upper and lower bounds of the locked and unlocked regimes when the detuning of the pump and slave laser is plotted as a function of the injection power. Our results are confirmed with an independent measurement using amplified spontaneous emission (ASE) spectroscopy as well as our theory, which takes account of the realistic quantum-well (QW) band structure and many-body effects. This method provides a new approach to measure the linewidth enhancement factor above …

An Electronically Tunable Resonator For Noise Control, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

Many engineering systems create unwanted noise that can be reduced by the careful application of engineering noise controls. When this noise travels down tubes and pipes, a tuned resonator can be used to muffle noise escaping from the tube. The classical examples are automobile exhaust and ventilation system noise. In these cases where a narrow frequency band of noise exists, a traditional engineering control consists of adding a tuned Helmholtz resonator to reduce unwanted tonal noise by reflecting it back to the source (Temkin, 1981). As long as the frequency of the unwanted noise falls within the tuned resonator frequency …

A New Portable, Pc Based, Usb Powered Dynamic Signal Analyzer, Charles Birdsong, George Ma, James Nieters, Justin Tang, Caine Yu

Mechanical Engineering

A new USB powered portable 4-channel real time Dynamic Signal Analyzer and its automotive applications are described. The design and architecture lend themselves to real time NVH measurements and analysis in the field, in-vehicle or on production lines. Built-in signal conditioning provides for direct sensor power while the embedded DSP provides for signal processing on-board. Performance and implementation of FFT, digital filters and order analyses are presented.

Feed-Forward Compensation Scheme For Feedback Circuits, Venugopal Gopinathan, Vladimir I. Prodanov

Electrical Engineering

A feed-forward compensated negative feedback circuit comprises an operational amplifier having an inverting and a non-inverting input and an output. A feedback element is connected between the output of the operational amplifier and its inverting input to form a negative feedback loop. The inverting input of the op-amp is driven with a first transconductance amplifier which produces an output current proportional to an input voltage. A feed-forward transconductance amplifier receives the input voltage and produces an inverted output current proportional to the input voltage. A feed-forward current is injected at the output of the operational amplifier. By providing at the …

Multimodal Fusion Of Polynomial Classifiers For Automatic Person Recognition, Charles C. Broun, Xiaozheng Zhang

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics are viewed as essential components of current and evolving technological systems. Consumers demand unobtrusive and noninvasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

There are two significant problem areas in current generation speaker verification systems. The first is the difficulty in acquiring clean audio signals (in all environments) …