Engineering Commons^™

Environmental Management Of Wastes In The Semiconductor And Electronics Industries, Samuel A. Vigil

Civil and Environmental Engineering

The management of wastes in the semiconductor and electronics industries requires a multidisciplinary approach that considers the health and safety of employees as well as the treatment and recycling of waste materials. The manufacturing of semiconductor devices requires the use of many toxic chemicals and gases. Air emissions from manufacturing tools must be carefully monitored both inside and outside of the fabrication facility. Liquid effluents must be collected and pretreated before discharge to local wastewater systems. The subsequent use and eventual discard of electronic devices such as television sets and personal computers by consumers has created a new set of …

Theory And Experiment Of High-Speed Cross-Gain Modulation In Semiconductor Lasers, Xiaomin Jin, T. Keating, Shun-Lien Chuang

Electrical Engineering

We present theory and experiment for the high-speed modulation response of a quantum-well (QW) laser in the presence of an external microwave modulated optical pump in the gain region. The model includes the effects of pump-induced stimulated recombination and cross-gain saturation. Expressions for the small-signal modulation response of the test laser under gain modulation are derived. We also present experimental results using a multiple-QW InGaAlAs Fabry-Perot (FP) laser at 1.552 μm as the test laser and an external pump by a 1.542 μm DFB laser. Comparison between electrical modulation and optical cross-gain modulation (XGM) of the test laser is also …

Effects Of Supplemental Viscous Damping On Inelastic Seismic Response Of Assymetric Systems, Cecilia A. Booker, Rakesh K. Goel

Civil and Environmental Engineering

This study investigates the effects of supplemental viscous damping on the seismic response of one-story, asymmetric-plan systems responding in the inelastic range of behavior. It was found that addition of the supplemental damping reduces not only deformation demand but also ductility and hysteretic energy dissipation demands on lateral load resisting elements during earthquake loading. However, the level of reduction strongly depends on the plan-wise distribution of supplemental damping. Nearly optimal reduction in demands on the outermost flexible-side element, an element generally considered to be the most critical element, was realized when damping was distributed unevenly in the system plan such …

A Growth Mixture Theory For Cartilage, Stephen M. Klisch, Robert L. Sah, Anne Hoger

Mechanical Engineering

In this paper we present a model of growth for cartilaginous tissues in which there exists a saturated solid matrix composed of multiple constituents that may grow and remodel independently of each other. Klisch and Hoger recently developed a general theory of volumetric growth for a mixture of ν-1 growing elastic materials and an inviscid fluid, which included a treatment of two special types of internal constraints that are relevant to cartilage. Here, that theory is specialized to construct a cartilage growth model. This theory allows the constituents of the solid matrix to grow independently of each other, and can …

A Comparison Of Two Actuators For A Semi-Active Helmholtz Resonator, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

Two electro-mechanical actuators are examined for a semi-active Helmholtz resonator acoustic device. The device is used to reflect narrow band noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the operation of the device. Two variations of an electro-mechanical actuator are considered here. The first uses a dual voice coil speaker with local feedback compensation and the second uses the same speaker without the compensation. It is shown that …

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily-shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the Finite Difference Time Domain (FDTD) and Method of Moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently used techniques, and can substantially improve design efficiency …

Development And Validation Of A Pedestrian Lower Limb Non-Linear 3-D Finite Element Model, Peter Schuster, Gopal Jayaraman

Mechanical Engineering

Lower limb injury is becoming an increasingly important concern in vehicle safety for both occupants and pedestrians. To enable vehicle manufacturers to better understand the biomechanical effects of design changes, it is deemed beneficial to employ a biomechanically fidelic finite element model of the human lower limb.

The model developed in this study includes long bones (tibia, fibula, femur) and flat bone (patella) as deformable bodies. The pelvis and foot bones are modeled as rigid bodies connected to the femur and tibia/fibula via rotational spring-dashpots. The knee is defined by scanned bone surface geometry and is surrounded by the menisci, …

Multi-Wavelength Polarization Scrambling Device, James R. Stimple, Dennis J. Derickson, Eugene Rudkevich

Electrical Engineering

A polarization scrambling device randomly varies the polarization states of multiple applied optical signals. The scrambling device includes a polarization scrambler coupled to a wavelength-dependent polarization randomizer having cascaded birefringent elements in which the axes of polarization of the cascaded elements are rotationally offset. The scrambling device causes random variations in the relative and the absolute polarization states of the applied optical signals. The birefringence, lengths, and number of cascaded birefringent elements are chosen to assure that the polarization states of optical signals at the different wavelengths are sufficiently randomized, even when the applied optical signals are closely spaced in …

Cheating: Student Attitudes And Practical Approachs To Dealing With It, Trevor S. Harding

Materials Engineering

The preliminary results of educational research conducted at Kettering University is described in which students in an introductory engineering materials course (MFGE-370) were asked to complete a survey on their perceptions of cheating. The overall objective of the research was to determine those things students believed constituted cheating, the frequency to which they cheat and their attitudes about what steps could be taken to curtail cheating within a course. Practical approaches to effectively dealing with cheating are also discussed including using learning objectives for writing fair tests, promoting group work through cooperative learning teams, holding review sessions before tests and …

A Multidisciplinary Polymer Electronics Laborary, David Braun, Kevin Kingsbury, Linda Vanasupa

Electrical Engineering

Semiconducting polymers blend several attractive features that enable inexpensive and unique applications. Forming the subjects of numerous research and development projects, semiconducting polymers also make excellent teaching tools. Since the materials and their applications benefit from intrinsically multidisciplinary approaches, polymer electronics exposes both students and faculty to fruitful interdisciplinary collaboration. This paper introduces semiconducting polymers, tours the Cal Poly polymer electronics lab facility, and summarizes lab projects and course modules completed to date.

Formulation, Realization, And Demonstration Of A Process To Generate Aerodynamic Metamodels For Hypersonic Cruise Vehicle Design, Robert Mcdonald, D.N. Mavris

Aerospace Engineering

The desire to facilitate the conceptual and preliminary design of hypersonic cruise vehicles has created the need for simple, fast, versatile, and trusted aerodynamic analysis tools. Metamodels representing physics-based engineering codes provide instantaneous access to calibrated tools. Nonlinear transformations extend the capability of metamodels to accurately represent a large design space. Independence, superposition, and scaling properties of the hypersonic engineering method afford an expansive design space without traditional compounding penalties. This one-time investment results in aerodynamic and volumetric metamodels of superior quality and versatility which may be used in many forms throughout early design. As a module, they can be …

Output Current Ripple Factor Performance Of Half-Wave Rectifier With And Without Freewheeling Diode, Taufik, Ali O. Shaban, Ahmad Nafisi

Electrical Engineering

The objective of this work is to investigate the ripple factor of half-wave rectifier circuits. The ripple factor is one of the important characteristics necessary when designing a power electronic converter. The ripple factor measures how much deviation the converter output parameter has, such as the output current, from its nominal designed value. In this paper the ripple factor of the output current of half-wave rectifiers is investigated. More specifically, the ripple factor of output current from more practical half-wave rectifiers that include inductive load with or without a freewheeling diode are analyzed and then compared to that of the …

Plastic Solder Paste Stencil For Surface Mount Technology, Christopher K. Wong, Daniel Waldorf

Industrial and Manufacturing Engineering

Solder paste masks or stencils are an integral part of the manufacturing process for surface mount PCBs. This study examines the feasibility of a process for rapid creation of a solder paste stencil using thermoplastic material. CNC laser cutting of the stencil geometry is replacing traditional use of chemical etching on metal sheets to produce stencils. Laser cutting has been used to improve process speed, accuracy, and cost. This research attempts to continue to simplify and reduce costs in the stencil making process by proposing as the stencil material a common thermoplastic that can be cut easily and quickly using …

Global Projects Prepare Wpi Students For The 21st Century, William W. Durgin, Donald N. Zwiep

Office of the Provost Scholarship

The WPI project based curriculum, which emphasizes discovery based learning are an alternative to the traditional information transfer process, has proved successful in delivering global engineering education. More than 25% of the learning process of the students is integrated into two formal projects, the Major Qualifying Project (MQP) which is designed as a capstone for professional technical competence and the Interactive Qualifying Project (IQP) which relates science and technology to societal concerns and student needs. Both the MQP and IQP may be completed on- or off-campus. Currently, over 50% of the graduating class will have completed one of the projects …

Effect Of Foreign Object Damage On The Fatigue Strength Of An Xd™ Γ-Tial Alloy, Trevor S. Harding, J. Wayne Jones

Materials Engineering

High cycle fatigue has become the leading cause of failure in gas turbine engine blades in recent years [1]. The majority of these failures were associated with surface damage such as foreign object damage (FOD). Therefore, the ability of a material to resist impact damage and the subsequent fatigue propagation of any cracks that may result has become a crucial design consideration. Substantial research has been conducted on the effects of simulated FOD in conventional turbine blade materials where the formation of cracks at the impact site was not a common occurrence [2, 3 and 4]. However, impacts of more …

Direct Displacement-Based Design Using Inelastic Design Spectrum, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

No abstract provided.

Lip Feature Extraction Towards An Automatic Speechreading System, Xiaozheng Zhang, Russell M. Mersereau

Electrical Engineering

The use of color information can significantly improve efficiency and robustness of lip feature extraction capability over purely grayscale-based methods. Edge information provides another useful tool in characterizing lip boundaries. In this paper we present a method of integrating both types of information to address the problem of lip feature extraction for the purpose of speechreading. We first examine various color models and view hue as an effective descriptor to characterize the lips due to its invariance to luminance and human skin color, and its discriminative properties. We use prominent red hue as an indicator to locate the position of …

The Effect Of Anisotrophy On The Potential Distribution In Biological Tissues And Its Impact On Nerve Excitation Simulations, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

Presents a finite difference solution of the potential distribution associated with electrical current stimulation in an anisotropic in-homogeneous tissue environment and compare it to the isotropic case. The results demonstrate that there can be significant errors associated with the assumption of isotropic tissue properties in calculating the potential distribution along an axon in nerve excitation simulations. These errors can have a significant impact on predicted nerve fiber recruitment patterns when evaluating the efficacy of specific surface or intramuscular stimulus electrode configurations. The results of this study also suggest when a more comprehensive tissue model should be implemented in an electrode …

Irrigation District Service In The Western United States, Charles M. Burt, Stuart W. Styles

BioResource and Agricultural Engineering

Data were obtained from 61 agricultural districts within the Mid-Pacific Region of the U.S. Bureau of Reclamation regarding the level of water delivery service provided to users, water pricing, associated characteristics, and plans for modernization. A flexibility index was developed and used by the writers to characterize the degree of water delivery flexibility provided by each district. The flexibility index provides a rating of 3–15 (15 being the highest value) based upon the frequency, rate, and duration of irrigation water delivery service to farmers. The data show that 42% of the districts received a flexibility score of 12 or greater, …

Relative Intensity Noise Characteristics Of Injection-Locked Semiconductor Lasers, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

An experimental and theoretical study of relative intensity noise (RIN) spectra of side-mode injection-locked Fabry–Perot semiconductor lasers is reported. It is shown that the injection-locking technique effectively increases the relaxation oscillation frequency from 4.5 GHz (free-running mode) to 12 GHz (injection-locked mode) and enhances relaxation peaks of the slave laser RIN spectra. Results from our theoretical model, which include the key parameters for semiconductor quantum-well lasers, such as the linewidth enhancement factor, the nonlinear gain saturation coefficients, and optical confinement factor, show good agreement with our experimental results.

Stability And Heat Transfer Characteristics Of Condensate Fluid Layers In Reduced Gravity, James C. Hermanson, Andreas N. Alexandrou, William W. Durgin, Peder C. Pedersen, Jeffrey S. Allen

Office of the Provost Scholarship

The focus of this ground-based program is the study of film condensation phenomena under variable, reduced-gravity conditions. Experimental tests, combined with numerical modeling, are employed to gain an improved understanding of the fundamental fluid physics responsible for condensate film growth, film instability and the resulting interfacial motion under variable gravity, and the corresponding implications for heat transfer. There has been relatively little research on the mechanisms operative at the film interface between condensed liquid and its vapor under reduced gravity conditions. Of particular interest are the stability characteristics of the condensate layer, and how they differ from those of films …

Thermally Treated Coal Tar Contaminated Soil As A Concrete Aggregate, Katherine E. Leblanc, John L. Durant, Christopher Swan, Michael J. Weaver, Daniel C. Jansen

Civil and Environmental Engineering

The current practice of landfilling thermally treated and untreated coal tar-contaminated soil is expensive, and it is a waste of a potentially useful material and landfill space. A less expensive and possibly more practical alternative is to use coal tar-contaminated soil as an aggregate in concrete. Because little work has been done in this area, the present study was undertaken to evaluate the effects of coal tar-contamination and thermal treatment on the physical properties of soil and the strength of concrete containing contaminated soil as an aggregate. Also assessed was the leachability of coal tar constituents (specifically, polycyclic aromatic hydrocarbons …

Field Case Histories For Spt-Based In Situ Liquefaction Potential Evaluation, K. Onder Cetin, Raymond B. Seed, Robb E.S. Moss, Armen Der Kiureghian, Kohji Tokimatsu, Leslie F. Harder, Jr., Robert E. Kayen

Civil and Environmental Engineering

This report provides documentation of the field performance case histories and site response analyses described in the report entitled "SPT-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Initiation Hazard," by Cetin, et al. (2000).

Table 3-5, taken from that report, summarizes the interpreted field performance case histories from the original database of Seed et al. (1984) that were found to conform to the standards of Data Classes A, B or C, and so were used in the studies of Cetin et al. Table 3-7, also taken from that report, summarizes the cases that were deleted from the overall database …

Benchmarking Irrigation, Charles M. Burt

BioResource and Agricultural Engineering

A few performance indicators (e.g., “efficiency”) have been included in irrigation jargon for many decades. However, at the Rome meeting we will have a comprehensive discussion on irrigation benchmarking. It will be easy to fall into a discussion of definitions and specifics. Prior to that, it might be helpful to consider the following aspects that will help to set the stage for the details:

Direct Stochastic Equivalent Linearization Of Sdof Smart Mechanical System, L. Duval, Mohammad N. Noori, S. Seelecke

Office of the Dean (CENG) Scholarship

The first and second moments of response variables for SDOF system with pseudoelastic material are obtained by a direct linearization procedure. This procedure is an adaptation of well-known statistical linearization methods, and provides concise, model-independent linearization coefficients. The method can be applied to systems that incorporate any SMA hysteresis model having a differential constitutive equation, and can be used for zero and non-zero mean random vibration. This implementation eliminates the effort of deriving linearization coefficients for new SMA hysteresis model. In this paper the complete statistical response of SDOF system containing a mass and a bar made of SMA is …

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the finite difference time domain (FDTD) and method of moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently used techniques, and can substantially improve the …

The Effect Of Impact Damage On The Room-Temperature Fatigue Behavior Of Γ-Tial, Trevor S. Harding, J. Wayne Jones

Materials Engineering

The relationship between impact damage and the fatigue behavior of γ-TiAl has been examined. Axial fatigue specimens fabricated from cast Ti-47.9Al-2.0Cr-1.9Nb (to be referred to as 48-2-2) and Ti-47.3Al-2.2Nb-0.5Mn-0.4W-0.4Mo-0.23Si (to be referred to as WMS) alloys were damaged by impact under controlled conditions with a 60 deg wedge-shaped indenter to simulate assembly-related damage in low-pressure turbine blades. The level of damage produced was quantified and found to correlate well with the peak load of the impact event. The WMS alloy exhibited a greater resistance to impact damage due to its higher yield strength and lamellar microstructure. A measure of the …

Wavelet-Based Approach For Structural Damage Detection, Z. Hou, Mohammad N. Noori, R. St. Amand

Office of the Dean (CENG) Scholarship

A wavelet-based approach is proposed for structural damage detection and health monitoring. Characteristics of representative vibration signals under the wavelet transformation are examined. The methodology is then applied to simulation data generated from a simple structural model subjected to a harmonic excitation. The model consists of multiple breakable springs, some of which may suffer irreversible damage when the response exceeds a threshold value or the number of cycles of motion is accumulated beyond their fatigue life. In cases of either abrupt or accumulative damages, occurrence of damage and the moment when it occurs can be clearly determined in the details …

Implementing An Engineering Teaching Development Program For Graduate Student Instructors, Sara Soderstrom, Christian Lorenz, Michael Keinath, Trevor S. Harding

Materials Engineering

The Engineering Teaching Development Project (ETDP), a pilot program started by the student chapter of ASEE at the University of Michigan, is a multi-component program designed to improve the long-term teaching skills of graduate student instructors (GSIs) in the College of Engineering. The first component of the ETDP is college-wide pedagogical workshop series. These workshops are conducted by nationally recognized engineering educators invited by the ASEE student chapter. The topics of these workshops include cooperative learning, diversity in the classroom, and classroom assessment techniques. These workshops offer a means of continual improvement for all of the educators in the university, …

Supplemental Viscous Damping Effects On Seismic Demands Of Linear Elastic Systems, Linda M. Tam, Rakesh K. Goel

Civil and Environmental Engineering

The objective of this study is to examine the effects of viscous supplemental damping on response quantities of asymmetric-plan structures responding in a linearly elastic fashion. The response quantities which will be investigated include: element deformations, base shears, and base torques. These response quantities will be normalized, evaluated, and then analyzed.

It is shown that supplemental damping is indeed effective in reducing element deformations and base torques. In some cases, supplemental damping is also effective in reducing base shears. In order to achieve the largest reduction in flexible element deformation, it is recommended that all fluid viscous dampers be placed …