Engineering Commons^™

Ghz Serial Passive Clock Distribution In Vlsi Using Bidirectional Signaling, Vladimir I. Prodanov, Mihai Banu

Electrical Engineering

We introduce a serial passive clock distribution technique allowing efficient and accurate skew removal at any arbitrary clock drop point. The passive transmission medium may be on-chip electrical transmission lines built in current IC technology or possible optical wave-guides in future developments. The proposed technique is naturally insensitive to practical loses and other non ideal effects and has the capability of covering large chip areas.

Super Barrier Rectifier - A New Generation Of Power Diode, V. Rodov, A. L. Ankoudinov, Taufik

Electrical Engineering

The main principle behind the new Super Barrier Rectifier (SBR) approach is to create the "Super" barrier for majority carriers without unreliable metal-semiconductor Schottky contact. SBR technology creates such barrier in the MOS channel. The height of this barrier can be easily adjusted by the doping concentration in the channel. This paper demonstrates that the new power diodes combine high performance and high reliability for low voltage applications (below 100V). The underlying concepts and analysis of operation are presented as well as the lab test results that compare performance and reliability between Schottky and the new SBR diode.

Synthesis Of Gold Micro- And Nano-Wires By Infiltration And Thermolysis, E.A. Olevsky, X. Wang, E. Bruce, M.B. Stern, S. Wildhack, F. Aldinger

Industrial and Manufacturing Engineering

An approach for synthesizing micro- and nano-sized gold wires by infiltration and thermolysis is investigated. A porous ZrO₂ ceramic preform with aligned pores obtained by unidirectional freezing and freeze-drying is employed as an infiltration template. The sintered porous ZrO₂ preform is then infiltrated by a brushing gold solution. The thermolysis is conducted at 600 °C in air. Micro- and nano-sized gold wires are developed within the walls of the pores after thermolysis. The diameter of the gold wires ranges from several hundred nanometers to several microns.

Investigation Of Coupled Lateral And Torsional Vibrations Of A Cracked Rotor Under Radial Load, Xi Mu, Jim Meagher, Clinton Judd

Mechanical Engineering

A practical cracked rotor model with two disks representing a turbine and generator is studied using a four degree of freedom model; two transverse displacements and two torsional angular displacements. The differential equations of a rotor with a crack, unbalance, and constant radial force are first derived in detail using energy principles. The nonlinearities related with a “breathing” crack are incorporated, which distinguishes this paper from others studying stiffness anisotropy of a rotor with a similar rotor configuration. Through numerical simulations, this paper demonstrates the lateral-torsional coupling that occurs with a shaft crack and predicts torsional critical speed frequencies at …

Response Of A Warped Flexible Rotor With A Fluid Bearing, Jim Meagher, Xi Wu, Chris Lencioni

Mechanical Engineering

A two complex degrees of freedom model is developed and compared to experimental data for various amounts of rotor bow and its orientation to mass imbalance of the rotor. The equation of motion is developed by adding constant forces that rotate with the rotor to a Bently-Muszynska two-mode isotropic rotor model with a plane journal bearing. Diagnostic information discernable from probes at the bearing is emphasized and compared to midspan response where previous research has concentrated. Good agreement between the analytical model and experiment demonstrate that the analysis presented can be useful to diagnose and balance residual shaft bow from …

Estimating The Probability Of Failure And Associated Risk Of The California Bay Delta Levee System, Robb E.S. Moss, J. Michael Eller

Civil and Environmental Engineering

Recent events in New Orleans have shown the magnitude of life loss and property damage that can occur due to the failure of man-made levees. The California Bay Delta and Sacramento levee systems in California pose a similar or greater level of risk to life and property. In order to effectively mitigate the hazard associated with levee failure a systematic evaluation of risk must be carried out. This paper presents preliminary research into the risk associated with the California Bay Delta. A comprehensive list of failure modes for man-made levees is presented. Preliminary empirical data on the temporal frequency of …

Flexible Irrigation Systems: Concept, Design And Application, John L. Merriam, Stuart W. Styles, Beau J. Freeman

BioResource and Agricultural Engineering

This paper presents the need, value, and concept of flexible irrigation water supply systems that can deliver water with flexibility in frequency, rate, and duration under the control of the farmer at the point of application using a limited rate arranged-demand or other schedule. It introduces the needed terminology including “congestion” — how much reserve time and capacity is required to assure water delivery at the frequency and rate desired. An illustrative design procedure for the necessary pipeline and reservoir capacities is illustrated. The techniques discussed emphasize the conversion of the economical steady supply canal flows to flexible on-farm usage …

F- 16xl Unsteady Simulations For The Cawapi Facet Of Rto Task Group Avt- 113, Scott A. Morton, David R. Mcdaniel, Russell M. Cummings

Aerospace Engineering

This work represents the USAF Academy portion of a culmination of three years of cooperative research in the Cranked Arrow Wing Aerodynamics International (CAWAPI) RTO Task Group, AVT-113. The objective of the group was to compute high resolution CFD simulations of a subset of the conditions created in the CAWAP flight test program managed by NASA Langley researchers and others. Seven flight conditions were chosen with four of them at symmetric conditions of medium to high angle of attack and subsonic Mach numbers, one symmetric condition at a transonic low angle of attack condition, and two conditions at medium angle …

Circulation Control And Its Application To Extreme Short Take-Off And Landing Vehicles, Julianna B. De La Montanya, David D. Marshall

Aerospace Engineering

Circulation Control is a high-lift method discovered in 1935 when Henry Coanda accidentally stumbled upon the technology. Research was conducted in the 1970‘s and 1980‘s to develop this technique, but the idea fell out of vogue until recently. Energy is introduced into the flow field by means of a jet ejected tangentially from a slot located near the trailing edge of the airfoil; thus changing the effective chamber of the airfoil and increasing lift. Extreme Short Take-Off and Landing (ESTOL) vehicles can use this technology to alleviate today‘s congested airports by reutilizing the small runways that are currently unexploited due …

The Role Of Error In The Conceptual Design Of A Transport Aircraft, Robert A. Mcdonald

Aerospace Engineering

A fidelity trade environment was demonstrated by using it to simulate a decision making process for a transport aircraft. This scenario was not possible without the fidelity trade environment. The role of system feedback and coupling in error stability was also investigated.
A sensitivity approach which relies on the system sensitivity matrix was used to rapidly approximate the propagation of error through the complex system. In verification tests, the sensitivity approach provided approximate results substantially similar to a Monte Carlo approach that was many orders of magnitude more expensive. The rapid sensitivity approach to modeling error propagation enabled the responsive …

The Happy Accidents Of Teaching Aircraft Design, David W. Hall, Russell M. Cummings

Aerospace Engineering

The aircraft design curriculum at Cal Poly has grown and evolved over the past decades to include a full year of senior aircraft design and an introductory aircraft design course in the sophomore year. The combination of sophomore and senior aircraft design courses has created the circumstance where a “cult” of aircraft design has developed. The curriculum is producing students who are enthusiastic and motivated education, as well as being competent designers after they graduate. A number of “happy accidents” has led to this fortunate situation, including: allowing the sophomores to perform a full aircraft design, having the sophomores work …

Wing-Nacelle Assembly Multidisciplinary Performance Optimization, Yevgeniy M. Gisin, David D. Marshall

Aerospace Engineering

The paper analyzes the aerodynamics benefits of above-wing mounting of turbofan engines and performs a trade-off study of the structural limitations with this mounting method. This research is based on the US Patent #6,308,913, aiming to quantify the actual benefit derived from the drag reduction measure described in the patent. The paper focuses on the analysis of a turbofan engine, which when installed above an aircraft’s wing creates a flow field optimized to reduce the overall drag experienced by the wing nacelle assembly. This installation is designed to reduce wave drag during transonic cruise and therefore the wing-nacelle geometry was …

Comparison Of Des And Urans For Unsteady Vortical Flows Over Delta Wings, L. A. Shiavetta, K. J. Badcock, Russell M. Cummings

Aerospace Engineering

The unsteady behaviour of delta wing vortical flows is still a subject which is a challenge for numerical methods, such as computational fluid dynamics. New approaches to turbulence modelling, such as detached eddy simulation (DES) have been proposed which allow for greater accuracy of the numerical predictions. However, this increase in accuracy comes with a considerable increase in computational expense compared to traditional turbulence modelling. This investigation considers the use of both DES and unsteady Reynolds averaged Navier-Stokes (URANS) turbulence methods in the prediction of unsteady vortical flows. Calculations using DES are initially considered for two test cases and the …

Flap Gate, Charles M. Burt

BioResource and Agricultural Engineering

ITRC began to investigate early designs of Flap Gates in 1992. The gates originated in The Netherlands in the 1940s, but no design criteria were available. ITRC developed an Excel design program that uses a combination of theory and coefficients from field results – and has continued to improve the program almost every year. District staff at Turlock ID and Chowchilla WD provided valuable feedback with early models. This report includes information on design, installation, maintenance, water conservation and efficiency, cost, use, and benefits.

ITRC Flap Gates are typically used with a concrete counterweight in situations where the gates are …

Biomechanics Of The Rabbit Knee And Ankle: Muscle, Ligament, And Joint Contact Force Predictions, Dustin M. Grover, Andrew A. Chen, Scott J. Hazelwood

Biomedical Engineering

Mathematical models of small animals that predict in vivo forces acting on the lower extremities are critical for studies of musculoskeletal biomechanics and diseases. Rabbits are advantageous in this regard because they remodel their cortical bone similar to humans. Here, we enhance a recent mathematical model of the rabbit knee joint to include the loading behavior of individual muscles, ligaments, and joint contact at the knee and ankle during the stance phase of hopping. Geometric data from the hindlimbs of three adult New Zealand white rabbits, combined with previously reported intersegmental forces and moments, were used as inputs to the …

Volume Effects On Fatigue Life Of Equine Cortical Bone, R. F. Bigley, J. C. Gibeling, S. M. Stover, S. J. Hazelwood, D. P. Fyhrie, R. B. Martin

Biomedical Engineering

Materials, including bone, often fail due to loading in the presence of critical flaws. The relative amount, location, and interaction of these flaws within a stressed volume of material play a role in determining the failure properties of the structure. As materials are generally imperfect, larger volumes of material have higher probabilities of containing a flaw of critical size than do smaller volumes. Thus, larger volumes tend to fail at fewer cycles compared with smaller volumes when fatigue loaded to similar stress levels. A material is said to exhibit a volume effect if its failure properties are dependent on the …

Digitally Controlled Synchronous Buck Converter, Taufik, M. Starman, M. Anwari

Electrical Engineering

The demand for high performance, more flexible and reconfigurable dc-dc converters has pushed dc-dc converter designers to seek for alternative ways to control the pulse-width modulated switch inside the dc-dc converter. During the past few years, efforts have been put forward both by academics and power semiconductor industries to phase out the most commonly used analog PWM controllers with digital controller with its associated software. This paper presents an experimental result of designing and building a 5W synchronous buck converter that employs a microcontroller to process the output voltage signal and translate it into PWM signal to control the switches …

Final Report: Production Of Biodiesel From Algae Applied To Agricultural Wastewater Treatment, Yarrow M. Nelson, Adam Feffer, Andrew Kean, Tryg Lundquist, Walter Mark, Linda Vanasupa, Sam Vigil, Ian Woertz

Civil and Environmental Engineering

No abstract provided.

Multiple-Model Framework For Assessment Of Real-Time Crash Risk, Anurag Pande

Civil and Environmental Engineering

This study is based on real-time models of risk assessment for rear-end and lane-change-related crashes on freeways. These models were developed in recent studies on the basis of historical crash data and corresponding traffic data collected through underground loop detectors on Interstate-4 in Orlando, Florida. In this study the potential of these models was explored for identification of crashes that were not part of the database used to develop the models. These crashes include single-vehicle crashes that might result from evasive actions taken by drivers to avoid vehicles in front (i.e., a rear-end crash) or in a neighboring lane (i.e., …

Backward And Forward Compatibility, Jianbiao Pan, Jasbir Bath, Xiang Zhou, Dennis Willie

Industrial and Manufacturing Engineering

In response to the European Union (EU) Restriction of Hazardous Substances (RoHS) and other countries’ impending lead-free directives, the electronics industry is moving toward lead-free soldering. Total lead-free soldering requires not only lead-free solder paste but also lead-free printed circuit board (PCB) finish and lead-free component/packages. Transitioning tin-lead (SnPb) soldering to totally lead-free soldering is a complex issue and involves movement of the whole electronics industry supply chain. In reality, there is a transition period.

Integrating Project-Based Learning Throughout The Undergraduate Engineering Curriculum, Richard N. Savage, Katherine C. Chen, Linda Vanasupa

Materials Engineering

Equipping engineering students with the skills and knowledge required to be successful global engineers in the 21st century is one of the primary objectives of undergraduate educators. Enabling students to practice self-directed learning, to find solutions to design problems that are sustainable and to recognize that they are part of a global community are just of few of our educational goals. Self-directed learning can define an individual’s ability to practice life-long learning. It places the responsibility on the individual to initiate and direct the learning process and can enable an individual to adapt to change. Project-based learning provides the contextual …

General Irrigation Consumer Bill Of Rights, Charles M. Burt

BioResource and Agricultural Engineering

Cal Poly ITRC, together with various irrigation industry leaders and the Irrigation Dealers Association of California, plus with assistance from the California Energy Commission and Pacific Gas & Electric Co., developed the Irrigation Consumer Bill of Rights (ICBR) in 1994.

Crash Data Analysis: Collective Vs. Individual Crash Level Approach, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Introduction

Traffic safety literature has traditionally focused on identification of location profiles where “more crashes are likely to occur” over a period of time. The analysis involves estimation of crash frequency and/or rate (i.e., frequency normalized based on some measure of exposure) with geometric design features (e.g., number of lanes) and traffic characteristics (e.g., Average Annual Daily Traffic [AADT]) of the roadway location. In the recent past, a new category of traffic safety studies has emerged, which attempts to identify locations where a “crash is more likely to occur.” The distinction between the two groups of studies is that the …

Using Underwater Remotely Operated Vehicles As An Engineering Education Tool, Hong Zhang, John Chen, Eric Constans

Mechanical Engineering

Starting in 2004, the Department of Mechanical Engineering at Rowan University introduced a new tool into its program: Remotely Operated Vehicles (ROVs). The tool is used at different aspects ofeducation. As a coursework project, graduating ME seniors researched, designed, built, competed and reported with underwater ROVs to assess their design skills before heading out to start their careers. It tests a wide range of engineering background in one single project and gauges the soft skills such as teamwork, self-learning, communication and evaluation. As a student research project, a multidisciplinary student team developed a robotic field ROV to help biological scientists …

Improving Factory Layout Under A Mixed Floor And Overhead Material Handling Condition, Manocher Djassemi

Industrial Technology and Packaging

Purpose –In spite of having a number of general-purpose algorithms for solving plant layout problems, facility planners may still face a challenging task to adjust these algorithms to handle special, but not uncommon, layout problems. The purpose of this study is to propose a new method for addressing the impact of overhead space utilization on a plant layout solution.

Design/methodology/approach –A new method for adjusting material flow under a mixed floor and overhead material handling condition is incorporated in an existing plant layout procedure. A case study involving the layout improvement in a lawn mower engine assembly facility …

Use Of Friction Stir Processing And Friction Stir Welding For Nitinol Medical Devices, Blair London, Murray Mahoney, Alan Pelton

Materials Engineering

Metallic materials may be joined utilizing a friction stir processing technique. The friction stir processing technique utilizes a shaped, rotating tool to move material from one side of the joint to be welded to the other without liquefying the base material.

The Paperless Factory: A Review Of Issues And Technologies, Manocher Djassemi, James A. Sena

Industrial Technology and Packaging

paper-based data management can be a bottleneck, slowing factory-wide information transfer. This study explores the evolution of paperless communication in a factory environment and reviews some of the key technologies that contribute to the implementation of a paperless system including digital communication, the virtual factory, computer-integrated manufacturing, and web-centric information flow. The challenges facing users of a paperless information system are also discussed.

Negative Conductance Power Amplifier, Vladimir I. Prodanov

Electrical Engineering

Power amplifiers are disclosed that demonstrate improved linearity and efficiency in applications requiring significant peak-to-average ratios (PAR). A power amplifier in accordance with the present invention comprises a first transistor in an input stage that converts DC power into AC power; and a second transistor in a negative conductance stage that has a current-voltage characteristic with at least two slopes. The at least two slopes of the current-voltage characteristic are separated by a break point that may be controlled. The power amplifier may also include a non-dissipative two-port device that has two AC ports. The non-dissipative two-port device has a …

Effect Of Chromium–Gold And Titanium–Titanium Nitride–Platinum–Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason B. Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications requires 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 for an optoelectronic application. Both Chromium and Titanium are used to promote adhesion between semiconductor substrates and sputtered gold films. However, both will be oxidized if they diffuse to the gold surface and result in the degradation of 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 …

Two In Vivo Surgical Approaches For Lumbar Corpectomy Using Allograft And A Metallic Implant: A Controlled Clinical And Biomechanical Study, Philbert Huang, Munish C. Gupta, Nesrin Sarigul-Klijn, Scott Hazelwood

Biomedical Engineering

Background context: Both bone graft and metallic implants have been used in combination with the necessary anterior rod or plate instrumentation to fill the voids left by vertebral body removal, with the ultimate goal of restoring stability. One type of device that has recently been introduced is an expandable titanium telescoping cage that is designed to be used as a strut implant to fill corpectomy defects. The use of these devices has met varying success. Acceptance by surgeons and spine biomechanicians has been limited by clinical failure with subsequent loss of reduction and increase in kyphosis. In order to further …