Engineering Commons^™

Varying The Time Delay Of An Action Potential Elicited With A Neural-Electronic Stimulator, Robert B. Szlavik, Frank Jenkins

Biomedical Engineering

There have been various theoretical and experimental studies presented in the literature that focus on interfacing neurons with discrete electronic devices such as transistors. It has also been demonstrated experimentally that neural-electronic devices can be used to elicit action potentials in a target neuron in close proximity to the neural-electronic stimulator. The time delay between stimulus and the onset of the neural action potential can be varied by varying the pulse amplitude and width generated by the neural-electronic stimulator (transistor).

Structural Graph Matching With Polynomial Bounds On Memory And On Worst-Case Effort, Fred W. Depiero

Electrical Engineering

A new method of structural graph matching is introduced and compared against an existing method and against the maximum common subgraph. The method is approximate with polynomial bounds on both memory and on the worst-case compute effort. Methods work on arbitrary types of graphs and tests with strongly regular graphs are included. No node or edge colors are needed in the methods; the common subgraph is extracted based in structural comparisons only. Monte Carlo trials are benchmarked with 100% additional (clutter) nodes. Results are shown to be typically within 1-2 nodes of the maximum common subgraph. Over 7500 test trials …

Electromagnetic Crosstalk Penalty In Serial Fiber Optic Modules, Xiaomin Jin, Keith D. Lystad, Musoke H. Sendaula

Electrical Engineering

Electromagnetic crosstalk poses a serious problem within today S advanced serial communication modules. A major detrimental effect is the degradation of receiver sensitivity in the presence of crosstalk noise. The mitigation of crosstalk penalty becomes increasingly more challenging as data rates increase for higher throughput and as module sizes shrink for increased port density. This paper is a study of the primary sources of crosstalk penalty in a 2.5 GB/s serial fiber optic transceiver and a 10Gb/s serial fiber optic transponder. A novel method for quantifying crosstalk penalty by observing a receiver’s bit-error-ratio (BER) versus transmitter to receiver signal phase …

Modeling And Simulation Research And Instruction At The U.S. Air Force Academy, Russell M. Cummings, Scott A. Morton, Keith Bergeron

Aerospace Engineering

Modeling and simulation has become a driving force within the engineering and science communities as the cost of, and time for, experimentation continues to rise. Some areas of study, such as chemistry and biology, may not even have the ability to fully evaluate certain processes experimentally, making modeling and simulation even more important. The situation has led many areas of research to the necessity of modeling and simulating various processes using computers. In addition, the rise in computational capabilities (the supercomputers of a decade ago are outmoded by the PC clusters of today), has led to a paradigm shift from …

Design Of Zebra Mussel Control Measures For Hydro-Electric Power Projects, G. Inci, C. J. Miller, N. Yesiller

Civil and Environmental Engineering

Zebra mussel, Dreissena polymorpha, is a biofouling organism that lives generally in freshwater ecosystems. Zebra mussel infestation has occurred at various freshwater structures and systems including raw water intakes, industrial and domestic distribution pipelines, and hydropower facilities at its native regions as well as distant locations. A study was conducted to perform risk assessment and to develop preventive measures for zebra mussel infestation at a planned hydroelectric power plant (Alpaslan II HEPP) in southeast Turkey. Zebra mussel is native to Anatolia region and existing hydropower facilities have significantly been affected by mussel infestation. The risk assessment was conducted by …

Geotechnical Reconnaissance Of The 2002 Denali Fault, Alaska, Earthquake, Robert E. Kayen, Eric Thompson, Diane Minasian, Robb E.S. Moss, Brian D. Collins, Nicholas Sitar, Douglas Dreger, Gary Carver

Civil and Environmental Engineering

The 2002 M7.9 Denali fault earthquake resulted in 340 km of ruptures along three separate faults, causing widespread liquefaction in the fluvial deposits of the alpine valleys of the Alaska Range and eastern lowlands of the Tanana River. Areas affected by liquefaction are largely confined to Holocene alluvial deposits, man-made embankments, and backfills. Liquefaction damage, sparse surrounding the fault rupture in the western region, was abundant and severe on the eastern rivers: the Robertson, Slana, Tok, Chisana, Nabesna and Tanana Rivers. Synthetic seismograms from a kinematic source model suggest that the eastern region of the rupture zone had elevated strong-motion …

Wire Bonding Challenges In Optoelectronics Packaging, Jianbiao Pan, Patrice Fraud

Industrial and Manufacturing Engineering

Wire bonding has been used in integrated circuit (IC) packaging for many years. However, there are many challenges in wire bonding for optoelectronics packaging. These challenges include bonding on sensitive devices, bonding over cavity, bonding over cantilevel leads and bonding temperature limitations. The optoelectronics package design brings another challenge, which requires wire bonding to have deep access capability. In this paper, the wire bonding technologies are reviewed and ball bonding and wedge bonding are compared. The variables that affect the wire bonding process are then discussed. Finally, the challenges of wire bonding in optoelectronics packaging are presented in detail.

An Intelligent Parameter Varying (Ipv) Approach For Non-Linear System Identification Of Base Excited Structures, Soheil Saadat, Gregory D. Buckner, Tadatoshi Furukawa, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

Health monitoring and damage detection strategies for base-excited structures typically rely on accurate models of the system dynamics. Restoring forces in these structures can exhibit highly non-linear characteristics, thus accurate non-linear system identification is critical. Parametric system identification approaches are commonly used, but require a priori knowledge of restoring force characteristics. Non-parametric approaches do not require this a priori information, but they typically lack direct associations between the model and the system dynamics, providing limited utility for health monitoring and damage detection. In this paper a novel system identification approach, the intelligent parameter varying (IPV) method, is used to identify …

Evaluation Of A Modified Mpa Procedure Assuming Higher Modes As Elastic To Estimate Seismic Demands, Anil K. Chopra, Rakesh K. Goel, Chatpan Chintanapakdee

Civil and Environmental Engineering

The modal pushover analysis (MPA) procedure, which includes the contributions of all significant modes of vibration, estimates seismic demands much more accurately than current pushover procedures used in structural engineering practice. Outlined in this paper is a modified MPA (MMPA) procedure wherein the response contributions of higher vibration modes are computed by assuming the building to be linearly elastic, thus reducing the computational effort. After outlining such a modified procedure, its accuracy is evaluated for a variety of frame buildings and ground motion ensembles. Although it is not necessarily more accurate than the MPA procedure, the MMPA procedure is an …

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 …

A Modal Pushover Analysis Procedure To Estimate Seismic Demands For Unsymmetric-Plan Buildings, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

An Erratum has been published for this article in Earthquake Engng. Struct. Dyn. 2004; 33:1429.

Based on structural dynamics theory, the modal pushover analysis (MPA) procedure retains the conceptual simplicity of current procedures with invariant force distribution, now common in structural engineering practice. The MPA procedure for estimating seismic demands is extended to unsymmetric‐plan buildings. In the MPA procedure, the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by non‐linear static analysis using the inertia force distribution for each mode, which for unsymmetric buildings includes two lateral forces and torque at …

Predicting Traffic Crashes Using Real-Time Traffic Speed Patterns, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Despite of the recent advances in traffic surveillance technology and ever-growing concern over traffic safety, there have been very few research efforts establishing Jinks between the real-time traffic flow parameters and crash occurrence. This study aims at the identification of the patterns in the freeway loop detector data, which potentially precede traffic crashes. This would have impOltant implications for Advanced Traffic Management Centers (ATMC). ATMCs could then be able to predict the potential for crashes on freeways and take action to reduce this hazard by warning drivers or introducing variable speed limits. Solution approach to this research problem essentially involves …

Development And Calibration Of A Large-Scale Thermal Conductivity Probe, James L. Hanson, Stefan Neuhaeuser, Nazli Yesiller

Civil and Environmental Engineering

A large-scale probe has been developed for measuring the thermal conductivity of geomaterials. The large probe was designed to conduct tests on materials containing large particles, materials with high heterogeneity, and materials with high stiffness. The probe has dimensions of 680 mm length and 15.9 mm diameter and was constructed of stainless steel tubing. The probe operates on the principle of heating an infinite line source in an infinite medium. Initially, parametric evaluations were conducted to determine the operational and test conditions for the large probe, including power level, heating duration, and zone of heating influence. Then, tests were conducted …

Identification Of Hysteretic Systems With Slip Using Bootstrap Filter, S. J. Li, Yoshiyuki Suzuki, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

Hysteretic models with slip are frequently used to predict the non-linear behaviour of many structural systems, for example wood buildings and reinforced concrete structures. A model, called SL model, which can describe the pinching of most practical hysteresis loops perfectly was proposed by Baber and Noori. This model is characterised by control parameters that have to be identified from observed experimental data. A method of estimating the parameters of SL model on the basis of input–output data based on Bayesian state estimation and bootstrap filter is suggested in this paper, which has the great advantages of being able to handle …

A Theoretical Analysis Of Long-Term Bisphosphonate Effects On Trabecular Bone Volume And Microdamage, Jeffry S. Nyman, Oscar C. Yeh, Scott J. Hazelwood, R. Bruce Martin

Biomedical Engineering

Bisphosphonates increase bone mass and reduce fracture risk, but their anti-resorptive action may lead to increases in fatigue microdamage. To investigate how bisphosphonate effects influence changes in bone volume and microdamage in the long term, a strain-adaptive model of bone remodeling and microdamage balance was developed for a continuum-level volume of postmenopausal trabecular bone by invoking Frost's mechanostat hypothesis. Both disuse and fatigue microdamage were assumed to stimulate the activation frequency of basic multicellular units (BMUs) such that bone remodeling served to remove excess bone mass and microdamage. Bisphosphonate effects were simulated as follows: low, intermediate, high, or complete suppression …

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 …

Efficient Orchestration Of Sub-Word Parallelism In Media Processors, John Y. Oliver, Venkatesh Akella, Frederic T. Chong

Electrical Engineering

Communication and multimedia applications with increased data rates and enhanced functionality continuously raise the bar for the computational requirements of future microprocessors. In order to meet these computational demands it is necessary to exploit sub-word parallelism efficiently. We propose to make sub-word data movement a first-class operation in microprocessor architectures by introducing a Sub-word Permutation Unit (SPU)in the execution pipeline. The SPU is evaluated in the context of the MMX media co-processor for the Intel Pentium architectures, but our results can be extended to any processor that supports sub-word parallelism. We find that the SPU all ws us to orchestrate …

Travelogue From The Materials World: A First Week Laboratory Activity, Katherine C. Chen, Blair London, Linda Vanasupa, Timothy T. Orling, Lisa Christensen

Materials Engineering

A fun, yet educational, laboratory activity was developed for the first week of an introductory Materials Engineering laboratory in order to set the stage for the rest of the quarter. The class is broken up into 8 teams, and each team performs a different experiment during each lab period. The teams then rotate lab experiments each week in a round robin manner, and thus teamwork is an important component of the class. In order to quickly promote team bonding the very first week, each team goes on a materials scavenger hunt together. A variety of materials-related items are to be …

Interactive Demonstrations And Laboratories Using Shape Memory Alloys, Wendy C. Crone, Eric J. Voss, Katherine C. Chen

Materials Engineering

Shape memory alloys (SMAs) constitute a unique class of materials that undergo a reversible phase transformation allowing the material to display dramatic stress-induced and temperature-induced deformations that are recoverable. Nickel titanium (NiTi) is a shape memory alloy used in a wide variety of biomedical, aerospace, automotive and other applications. The austenite-martensite phase transformation that occurs in these alloys with changes in temperature or applied stress is responsible for the unique properties of this material. The unusual behavior of SMAs provides an exciting way to engage students and can be incorporated into a variety of courses under topics such as phase …

Synchroscalar: A Multiple Clock Domain, Power-Aware, Tile-Based Embedded Processor, John Y. Oliver, Ravishankar Rao, Paul Sultana, Jedidiah Crandall, Erik Czernikowski, Leslie W. Jones, Iv, Diana Franklin, Venkatesh Akella, Frederic T. Chong

Electrical Engineering

We present Synchroscalar, a tile-based architecture for embedded processing that is designed to provide the flexibility of DSPs while approaching the power efficiency of ASICs. We achieve this goal by providing high parallelism and voltage scaling while minimizing control and communication costs. Specifically, Synchroscalar uses columns of processor tiles organized into statically-assigned frequency-voltage domains to minimize power consumption. Furthermore, while columns use SIMD control to minimize overhead, data-dependent computations can be supported by extremely flexible statically-scheduled communication between columns. We provide a detailed evaluation of Synchroscalar including SPICE simulation, wire and device models, synthesis of key components, cycle-level simulation, and …

One-Tap Wideband I/Q Compensation For Zero-If Filters, Peter Kiss, Vladimir I. Prodanov

Electrical Engineering

The I/Q imbalance is one of the performance bottlenecks in transceivers with stringent requirements imposed by applications such as 802.11a. The mismatch between the frequency responses of two analog low-pass filters, used, e.g., for channel selection in zero-IF receivers, makes this I/Q imbalance frequency dependent. Usually, frequency-dependent I/Q mismatch is estimated and corrected by adaptive techniques, which are complex to implement and may converge slowly due to noise. In this work, a simple, delay-based I/Q compensation scheme is proposed based on an extensive statistical analysis. Its digital implementation uses only two coefficients, which are tuned by a one-step two-tone error …

The Influence Of Academic Dishonesty On Ethical Decision- Making In The Workplace: A Study Of Engineering Students, Trevor S. Harding, Donald D. Carpenter, Cynthia J. Finelli, Honor J. Passow

Materials Engineering

According to studies conducted over the past four decades, engineering students self-report high frequencies of academic dishonesty (cheating) while in college. Research on college students in all fields has indicated that such behavior is more common among students who participate in academic dishonesty at the high school level and that it is correlated with other deviant or unethical behaviors, such as petty theft and lying. If, in fact, such correlations do exist, one might hypothesize that there is also a relationship between academic dishonesty in college and deviant or unethical behavior in professional practice. Placing this relationship in the context …

Life Cycle Assessment As A Tool For Green Manufacturing Education, Trevor S. Harding

Materials Engineering

The design and production of engineering products that have a reduced impact on the environment and human health has increasingly become a strategic goal of corporations. Consequently, starting engineers will need to be educated in green design techniques. One method that is particularly attractive to engineers is Life Cycle Assessment (LCA). LCA is an objective approach to evaluating the environmental burden of a product, process or activity by identifying and quantifying material and energy usage and waste outputs at every life stage. LCA involves three steps: identification of scope of analysis, life cycle inventory, and impact analysis. Such an approach …

Does Academic Dishonesty Relate To Unethical Behavior In Professional Practice? An Exploratory Study, Trevor S. Harding, Donald D. Carpenter, Cynthia J. Finelli, Honor J. Passow

Materials Engineering

Previous research indicates that students in engineering self-report cheating in college at higher rates than those in most other disciplines. Prior work also suggests that participation in one deviant behavior is a reasonable predictor of future deviant behavior. This combination of factors leads to a situation where engineering students who frequently participate in academic dishonesty are more likely to make unethical decisions in professional practice. To investigate this scenario, we propose the hypotheses that (1) there are similarities in the decision-making processes used by engineering students when considering whether or not to participate in academic and professional dishonesty, and (2) …

Investigation Of Subcritical Fatigue Crack Growth In Gamma Titanium Aluminides, Blair London

Materials Engineering

Our titanium aluminide alloy was readily heat treated to a fully lamellar state by holding at 1345C for 1.5 hours and furnace cooling resulting in a grain size of 330 muon m. The yield stress, ultimate stress, and total elongation were 315MPa, 465MPa, and 0.46% respectively. The fully lamellar microstructure shows significant work hardening. No long cracks initiated at R=0.1 and variation max=300MPa with up to 1.4 million cycles.

I/Q Imbalance Of Two-Path Ladder Filters, Peter Kiss, Vladimir I. Prodanov

Electrical Engineering

The frequency-(in)dependent I/Q imbalance of analog filters is a significant contributor to the tight noise budget of high-performance wireless applications, such as 802.11a wireless LANs. This paper proposes a “frequency-dependent” statistical I/Q-imbalance analysis method for two-path filters, which can be configured for both low-IF and zero-IF architectures. A 7-pole complex band-pass ladder filter is analyzed, and it shows large image rejection ratio (rms IMR > 43.7 dB for 3 σ). The same filter, but reconfigured as a pair of real low-pass filters, achieved about 13-dB less IMR. These results suggest a low-IF architectural choice to combat the I/Q imbalance of two-path …

Evaluation Of Nonlinear Static Procedures Using Strong-Motion Building Records, Rakesh K. Goel

Civil and Environmental Engineering

The objective of this investigation is to evaluate the FEMA-356 Nonlinear Static Procedure (NSP) and a recently developed Modal Pushover Analysis (MPA) procedure using recorded motions of buildings that were damaged during the 1994 Northridge earthquake. It is found the FEMA-356 NSP typically underestimates the drifts in upper stories and overestimates them in lower stories. The MPA procedure provides much-improved estimates of the response compared to the FEMA-356 NSP. In particular, the MPA procedure, unlike the FEMA-356 NSP, is able to capture the effects of higher modes.

Evaluation Of Nonlinear Static Procedures Using Strong-Motion Building Records, Rakesh K. Goel

Civil and Environmental Engineering

The objective of this investigation is to evaluate the FEMA-356 Nonlinear Static Procedure (NSP), the Sum-Difference procedure, and the Modal Pushover Analysis (MPA) procedure using recorded motions of buildings that were damaged during the 1994 Northridge earthquake. It is found the FEMA-356 NSP and the Sum-Difference procedures typically underestimates the drifts in upper stories and overestimates them in lower stories. The MPA procedure provides estimates of drifts that are better compared to the FEMA-356 NSP and the Sum-Difference procedure. In particular, the MPA procedure is able to capture the effects of higher modes.

Characterization Of Aerobic And Anaerobic Microbial Activity In Hydrocarbon-Contaminated Soil, Lynne C. Maloney, Yarrow M. Nelson, Christopher L. Kitts

Civil and Environmental Engineering

Microbial activity in hydrocarbon-contaminated soil was characterized and quantified to determine the potential for natural attenuation at a former oil field in California. Plate counts, direct microscopic counts, and carbon dioxide and methane production rates were used to quantify the populations and activity of soil microorganisms. Terminal restriction fragment (TRF) analysis provided preliminary identification of dominant microorganisms and community shifts as depth and contaminant concentrations changed. Plate counts under aerobic conditions resulted in 1.5 to 22 × 10⁶ colony-forming units (CFU) per gram of soil, and direct microscopic counts of total bacteria were 3 to 33 × 10^{6 …}

Biological Feasibility And Optimization Of Biosparging At A Hydrocarbon-Contaminated Site, Jason G. Waudby, Yarrow M. Nelson

Civil and Environmental Engineering

The purpose of this study was to identify any biological/chemical factors which may be limiting the biodegradation of total petroleum hydrocarbon (TPH) contaminants at a biosparge site located at a former oil field near Guadalupe, California. Laboratory experiments using a combination of respirometry and TPH analyses were conducted to determine if biodegradation of TPH at the site is limited by a lack of hydrocarbon-degrading microorganisms, depleted inorganic nutrient concentrations, insufficient dissolved oxygen supply, or the chemical composition of the partially biodegraded petroleum constituents in the groundwater. No increase in total CO₂ production was observed in samples with added nutrients, …