Engineering Commons^™

Multiple Differential Pair Transitor Architecture Having Transconductance Proportional To Bias Current For Any Transitor Technology, Vladimir I. Prodanov

Electrical Engineering

A multiple differential pair circuit is disclosed having a transconductance, g_m, proportional to the bias current, I₀, for any transistor technology. The transistors utilized to construct each of the differential transistor pairs in a multiple differential pair circuit operate in a non-exponential voltage-current (V-I) region. As multiple differential pair circuits are linearized, the effective transconductance, g_m, becomes (i) linearly dependent on bias current, and (ii) insensitive to the voltage-current (V-I) characteristics of the utilized devices. Methods and apparatus are disclosed that provide a linear transconductance, g_m, with respect to the bias current, …

Cultivating Graduate Students: Techniques To Inspire Effective Research, David Braun, Linda Vanasupa, Blair London, Kevin Kingsbury, Heather Smith

Electrical Engineering

Each year, U.S. institutions grant well over 10,000 bachelor's degrees in science and engineering. However, only a small fraction of those students pursue graduate study. Many who do often experience great difficulty partly due to a lack of preparation for research: the nature of research is inherently foreign to those who are accustomed to studying course material and demonstrating their mastery of it by passing an exam. Carefully involving undergraduates in research can be an effective means for inspiring students to pursue graduate study. We have found that one can create a positive research experience for the student by implementing …

Hide Glue Applicator, Chris Campo, Benjamin Carrasco, Elias Saliba

Mechanical Engineering

This study investigates the challenges inherent in applying hide glue in the crafting of violin and other stringed instruments. Hide glue, derived from animal collagen and protein, is essential for creating durable bonds that allow for necessary adjustments during fabrication. However, its meticulous heating and maintenance requirements pose logistical obstacles for luthiers lacking viable alternatives. To tackle this issue comprehensively, our project comprises several key components.

Initially, we conducted an in-depth analysis of the hide glue application process, delineating procedural steps and techniques to establish our design criteria and constraints. This foundational understanding formed the basis for further exploration. Additionally, …

Transient Response Of Passive Matrix Polymer Led Displays, David Braun, K. Erickson, G. Yu

Electrical Engineering

Video displays based on polymer and organic displays require high resolution and high data rates. However, the transient response of passive matrix displays based on polymer and organic light-emitting diodes limits display resolution, image uniformity, and image contrast. We use circuit simulation in order to quantify these consequences. This work analyzes how the transient response depends on display resolution, display geometry, pixel position, and row and column electrode design. We conclude that advanced display designs can achieve uniform images at high resolution and contrast.

Method To Optimize Polymer Film Spin Coating For Polymer Led Displays, M. Cecchi, H. Smith, David Braun

Electrical Engineering

Research and development of displays and image sensors based on semiconducting polymers require design of new polymer materials and evaluation of film properties. Application of statistical methods can expedite process development. Optimizing device performance entails determining the effect of several process parameters, necessitates numerous samples, and may consume more scarce new material than desired. Uniform film thickness, with no voids, pinholes, inhomogeneities, or particulate contamination across the substrate can improve display efficiency and uniformity. After performing and analyzing a two-cubed full-factorial experiment with three replicated center points, this paper concludes that spin velocity and polymer concentration have statistically significant effects …

On The Solution Of A Class Of Large Body Problems With Partial Circular Symmetry (Multiple Asymmetries) By Using A Hybrid-Dimensional Finite-Difference Time-Domain (Fdtd) Method, Dean Arakaki, Wenhua Yu, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve a large body scattering problem, viz. a paraboloid reflector antenna system, with only partial circular symmetry. The asymmetry in the system is introduced by two factors, viz. the microstrip feed and an inhomogeneous radome. The paper presents a novel approach, based on the equivalence and reciprocity principles and the “equivalent” aperture theory, to overcome the asymmetry problem. The technique thereby enables substantial computational efficiencies by analyzing the majority of the three-dimensional (3-D) computational domain in an effective two-dimensional (2-D) simulation, with the remainder being analyzed using a 3-D algorithm.

Flap Gate Design For Automatic Upstream Canal Water Level Control, Charles M. Burt, Russdon Angold, Mike Lehmkuhl, Stuart Styles

BioResource and Agricultural Engineering

The EXCEL design procedure for a simple hydraulic flap gate for automatic upstream canal water level control is provided. Basic configurations were developed in The Netherlands in the 1920s and have recently been used in Indonesia, the Dominican Republic, and Nigeria. Four irrigation districts in the San Joaquin Valley of California have constructed and installed over 60 properly functioning flap gates. The gates can be installed within 2 h, but require free discharge conditions and in practice are limited to controlling water depths of about 1 m or less.

Effects Of Supplemental Viscous Damping On Inelastic Seismic Response Of Asymmetric Systems, Rakesh K. Goel

Civil and Environmental Engineering

This paper investigates the effects of supplemental viscous damping on the seismic response of one‐storey, asymmetric‐plan systems responding in the inelastic range of behaviour. 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 Mechanistic Model For Internal Bone Remodeling Exhibits Different Dynamic Responses In Disuse And Overload, Scott J. Hazelwood, R. Bruce Martin, Mark M. Rashid, Juan J. Rodrigo

Biomedical Engineering

Bone is a dynamic tissue which, through the process of bone remodeling in the mature skeleton, renews itself during normal function and adapts to mechanical loads. It is, therefore, important to understand the effect of remodeling on the mechanical function of bone, as well as the effect of the inherent time lag in the remodeling process. In this study, we develop a constitutive model for bone remodeling which includes a number of relevant mechanical and biological processes and use this model to address differences in the remodeling behavior as a volume element of bone is placed in disuse or overload. …

Direct Displacement‐Based Design: Use Of Inelastic Vs. Elastic Design Spectra, Anil K. Chopra, Rakesh K. Goel

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. We demonstrate that the procedure provides the following: (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 …

Method And Apparatus For Adaptive Process Control Of Critical Dimensions During Spin Coating Process, Richard N. Savage, Emir Gurer

Materials Engineering

A spin coating process for controlling the mean thickness of photoresist on the surface of a semiconductor wafer. The wafer surface has a central axis normal to the surface. The process comprises the steps of applying the solution to the wafer surface and spinning the wafer about the central axis at a spindle speed until the solution has dried. The spindle speed is a function of the desired mean thickness of the photoresist, the barometric pressure and the relative humidity. The spindle speed is determined from a statistical model described by the equation: MT=A+BxRH+CxBP+D/SS^1/2 wherein: MT is mean thickness …

Adjustable Magnetic Coupler, Charles M. Burt

BioResource and Agricultural Engineering

Efficiency in terms of power consumption is vital and continues to be increasingly important. The use of adjustable speed pumps can reduce energy consumption and improve controllability of pressure or flows. One such technology, the MagnaDrive coupler, has been developed for service in a variety of applications.

Pumped Storage: Simple Changes, Big Savings, Charles M. Burt

BioResource and Agricultural Engineering

Several California irrigation districts achieved savings on electrical energy charges by implementing various types of pumped storage systems. Pumped storage uses some type of reservoir to store pumped water at a higher elevation than the original water supply. During times of peak statewide electricity demand, pumping is reduced while water is withdrawn from the reservoir which acts as a buffer.

Evaluation Of Retrievable Drip Tape Irrigation Systems, Charles M. Burt, Jess T. Barreras

BioResource and Agricultural Engineering

California growers of lettuce, broccoli, celery, and cauliflower have long been leaders in drip tape applications. Starting in the early 1990s, large acreages of buried, subsurface drip irrigation (SDI) were installed with the intent of leaving the tape in the ground for up to 10 years (Burt and Styles, 1999). Tape burial depths were typically 20 - 25 cm below the soil surface. Although yields and irrigation efficiencies typically increased, there were numerous challenges with SDI. Since the tape was buried, such issues occurred as gopher damage, problems with root intrusion, soil back-siphonage when the system was shut off, damage …

A Modal Pushover Analysis Procedure To Estimate Seismic Demands For Buildings: Theory And Preliminary Evaluation, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

The principal objective of this investigation is to develop a pushover analysis procedure based on structural dynamics theory, which retains the conceptual simplicity and computational attractiveness of current procedures with invariant force distribution, but provides superior accuracy in estimating seismic demands on buildings.

The standard response spectrum analysis (RSA) for elastic buildings is reformulated as a Modal Pushover Analysis (MPA). The peak response of the elastic structure due to its nth vibration mode can be exactly determined by pushover analysis of the structure subjected to lateral forces distributed over the height of the building according to s^*_n = …

Enhanced Biodegradation Of Hydrocarbon Contaminants Using Photocatalytic Pretreatment, Chad E. Green, Anita Stansberry, Jeff Sczechowski, Yarrow Nelson

Civil and Environmental Engineering

Photocatalysis was investigated as a pretreatment for hydrocarbon groundwater contamination at an abandoned oil field in Guadalupe, CA. A laboratory photoreactor, with a UV fluorescent lamp submerged in a suspension of TiO₂ catalyst particles, was used to determine oxidation rates and the increase in biodegradability of the hydrocarbon mixture. Chemical oxidation demand (COD) and 5-day biological oxygen demand (BOD₅) were measured as a function of exposure time using standard methods. During eight-hour photoreactor runs in a nitrogen atmosphere, the COD of diluent solutions in de-ionized water and diluent solutions in simulated groundwater both decreased by approximately 50%, …

Bottom Mounted Doppler Flow Meter For Canals, Stuart W. Styles

BioResource and Agricultural Engineering

Doppler technology, similar to that used by meteorologist to track weather patterns, has been developed and expanded to fill the need for advanced water flow measurement technology that is relatively easy to use, applicable to various hydraulic conditions, and very accurate. This report discusses the operation of doppler units, provides a comparison of the technology, benefits, cost, and use.

Load Monitoring System, Charles M. Burt

BioResource and Agricultural Engineering

Arvin-Edison Water Storage District received a loan - from the CEC's loan program for the development of new energy conservation technology - in 1995 to develop a program with variable frequency drives. This report discusses the design of the "Load Monitoring System", cost, the need for such a system, initial start-up challenges, configuration options, and benefits.

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 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 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 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 …

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.

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 …

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 …