Engineering Commons^™

How We Learned To Love The Phase Diagram With A Ti-Cr Alloy Characterization Lab, Katherine C. Chen

Materials Engineering

While many students learn how to read and use a phase diagram in introductory materials courses, greater appreciation for such a tool can be garnered through the laboratory setting. A laboratory module for a “Structures of Materials” class (a “core class” for materials majors) has been developed to demonstrate the usefulness of phase diagrams, as well as, to emphasize the connections among processing, structure, and properties. Competence in determining stable phases, phase compositions, and mass fractions of phases are not the end goal, per se, but transpire since the skills are required to help solve a puzzle. Students are given …

Apparatus, Method And System For Common-Mode Stabilization In Circuits Having Differential Operation, George Palaskas, Vladimir Prodanov

Electrical Engineering

A system, method and apparatus are disclosed for common-mode voltage feedback. The preferred system includes a plurality of differential circuits, a corresponding plurality of common-mode voltage detectors, a corresponding plurality of buffer circuits, and a common-mode control circuit. Each differential circuit is operative to produce a first differential output voltage and a second differential output voltage. Each corresponding common-mode voltage detector is operative to provide a common-mode voltage from the first differential output voltage and the second differential output voltage. The common-mode control circuit provides a control voltage signal from the common-mode voltage and from a reference voltage. Each buffer …

A Neuromorphic Controller For A Distillation Column, Xiao-Hua Yu

Electrical Engineering

This paper investigates the design of a neural network based controller to control the concentration of the overhead and bottom product in the model of a distillation column. Satisfactory computer simulation results of this approach are obtained.

Cmos Transconductor With Increased Dynamic Range, Vladimir I. Prodanov

Electrical Engineering

A CMOS transconductor that operates with increased dynamic range while maintaining one or more other basic operating characteristics at substantially the same value in comparison to a prior art transconductor circuit is provided. One embodiment, among others, comprises an input stage circuit comprising several pluralities of transistors with each plurality configured such that certain terminals of the transistors are electrically connected, and the several pluralities are electrically interconnected through one or more terminals of each plurality. Another embodiment comprises modifying an input stage of an existing transconductor circuit to provide a transconductor circuit that operates with increased dynamic range while …

Multidisciplinary Applications Of Detached-Eddy Simulation To Separated Flows At High Reynolds Numbers, Scott A. Morton, Matt Steenman, Russell M. Cummings, James R. Forsythe, Kenneth E. Wurtzler, Kyle D. Squires, Shawn H. Woodson, Phillippe R. Spalart

Aerospace Engineering

We focus on multidisciplinary applications of detached-eddy simulation (DES), principally flight mechanics and aeroelasticity. Specifically, the lateral instability (known as abrupt wing stall) of the preproduction F/A-18E is reproduced using DES, including the unsteady shock motion. The presence of low frequency pressure oscillations due to shock motion in the current simulations and the experiments motivated a full aircraft calculation, which showed low frequency high-magnitude rolling moments that could be a significant contributor to the abrupt wing stall phenomenon. DES is also applied to the F-18 high angle of attack research vehicle (HARV) at a moderate angle of attack to reproduce …

Students' Perceptions Of Both The Certainty And The Deterrent Effect Of Potential Consequences Of Cheating, Cynthia J. Finelli, Trevor S. Harding, Donald D. Carpenter, Honor J. Passow

Materials Engineering

No abstract provided.

Phytostimulation Of Hydrocarbon Biodegradation By Arroyo Willows In Laboratory Microcosms, Kenneth M. Hoffman, Yarrow M. Nelson

Civil and Environmental Engineering

Controlled laboratory microcosms with and without Arroyo Willows (Salix lasiolepis) were used to elucidate potential mechanisms of phytoremediation of hydrocarbon-contaminated groundwater at a contaminated oil field near Guadalupe, CA. Laboratory control allows us to examine the synergistic effects between the plants themselves and the rhizobial bacteria associated with them. Laboratory microcosms were set up in triplicate with (1) sodium azide-inhibited soil, (2) soil with active bacteria, and (3) soil with active bacteria and willows. Hydrocarbon-contaminated groundwater was recirculated through the root zone for 105 days. Biodegradation rates were estimated by measuring total petroleum hydrocarbon (TPH) concentration and monitoring chemical oxygen …

Optimization Of High-Strength Hydrocarbon Biodegradation Using Respirometry, Bunkim G. Chokshi, Yarrow M. Nelson

Civil and Environmental Engineering

Laboratory respirometry experiments were conducted on mixtures of soil and oily sludge to estimate biodegradation rates by CO₂ production rates and determine optimum conditions for biodegradation of high-strength hydrocarbon waste products. These experiments were used to determine a suitable range of total petroleum hydrocarbon (TPH) concentration for biological treatment and to optimize for nutrient addition and moisture content. CO₂ production rates from biological respiration of hydrocarbon-contaminated soil were maximized at concentrations of 3-9% TPH (30,00090,000 mg/kg TPH). CO₂ production rates decreased dramatically at concentrations above 9% TPH, indicating that either these concentrations are lethal to microbes present, …

Experimental Investigation Of Dynamic Response Of Compacted Clayey Soils, Gokhan Inci, Nazli Yesiller, Takaaki Kagawa

Civil and Environmental Engineering

A study was conducted to determine the dynamic properties of compacted clayey soils subjected to low amplitude vibration. A fast and simple ultrasonic pulse transmission method was used. Tests were conducted on three clayey soils with low to high plasticity compacted using standard and modified Proctor effort over a range of water contents. The samples were allowed to dry after compaction and P-wave velocity, S-wave velocity, Poisson's ratio, and shear modulus were determined. The effects of soil type, compaction conditions, and degree of saturation on the dynamic response of the soils were investigated. The elastic wave velocities and the dynamic …

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.

Cpt-Based Probabilistic Assessment Of Seismic Soil Liquefaction Initiation., Robb E.S. Moss

Civil and Environmental Engineering

The correlation of seismic field performance with in situ index test results has been proven to be a reliable method for defining the threshold between liquefaction and non-liquefaction. The objective of this research was to define in the most accurate and unbiased manner possible the initiation of seismic soil liquefaction using the Cone Penetration Test (CPT). Case histories of occurrence and non-occurrence of soil liquefaction were collected from seismic events over the past three decades. These were processed to develop improved CPT-based correlations for prediction of the likelihood of “triggering” or initiation of soil liquefaction during earthquakes. Important advances over …

Gis Mapping For Irrigation District Rapid Appraisals, Daniel Howes, Charles M. Burt, Stuart W. Styles

BioResource and Agricultural Engineering

Geographic information system (GIS) mapping is slowly becoming commonplace in irrigation districts as the need for more accurate and organized data becomes increasingly important. The Irrigation Training and Research Center (ITRC) at California Polytechnic State University, San Luis Obispo commonly uses GIS as a tool in technical assistance packages for irrigation districts. One of the challenges in developing a strategic irrigation district modernization plan is to organize spatial data in such a way that various options can be easily understood. ITRC uses a combination of commercially available software with web-downloadable maps and photographs to organize and present the spatial information. …

Ultrasonic Flowmeters In Determination Of Correlation Functions Of Velocity And Ultrasound Wave Fluctuations In Grid-Generated Turbulence, Tatiana A. Andreeva, William W. Durgin

Office of the Provost Scholarship

The paper is devoted to the experimental investigation of the statistical characteristics of the grid-generated turbulence produced in a wind tunnel. Ultrasonic time-of-flight method using dual transducers is utilized to develop a methodology for determination of the correlation functions of turbulent velocity and sound speed fluctuations. The ultrasonic flowmeter equation is considered in the form that includes effects of turbulent velocity and sound speed fluctuations. The influence of temperature inhomogeneities on ultrasonic wave propagation is investigated using a set of experiments with a heated grid. Utilization of high-speed digital data acquisition cards and LabView software for the experiments allows collecting …

Method And Apparatus For Modulating Digital Data, Jack Glas, Vladimir I. Prodanov, Maurice Tarsia

Electrical Engineering

The modulator includes an oscillator generating signals, each having a different phase, and a selector receiving digital data. When the digital data received by the selector changes logic state, the selector supplies a first and second plurality of signals generated by the oscillator to first and second non-linear amplifiers, respectively. An adder then adds the output of each amplifier to generate a radio frequency output.

Development Of An Atrophic Nonunion Model And Comparison To A Closed Healing Fracture In Rat Femur, Takeshi Kokubu, David J. Hak, Scott J. Hazelwood, A. Hari Reddi

Biomedical Engineering

Although most fractures heal, some fail to heal and become nonunions. Many animal models have been developed to study problems of fracture healing. The majority of nonunion models have involved segmental bone defects, but this may not adequately represent the biologic condition in which nonunions clinically develop. The objective of the present study is to develop a nonunion model that better simulates the clinical situation in which there is soft tissue damage including periosteal disruption and to compare this model to a standard closed fracture model utilizing identical fracture stabilization, providing a similar mechanical environment. A total of 96 three …

Osteon Pullout In The Equine Third Metacarpal Bone: Effects Of Ex Vivo Fatigue, L. P. Hiller, S. M. Stover, V. A. Gibson, J. C. Gibeling, C. S. Prater, S. J. Hazelwood, O. C. Yeh, R. B. Martin

Biomedical Engineering

An important concept in bone mechanics is that osteons influence mechanical properties in several ways, including contributing to toughness and fatigue strength by debonding from the interstitial matrix so as to "bridge" developing cracks. Observations of "pulled out" osteons on fracture surfaces are thought to be indicative of such behavior. We tested the hypothesis that osteon pullout varies with mode of loading (fatigue vs. monotonic), cortical region, elastic modulus, and fatigue life. Mid-diaphseal beams from the dorsal, medial, and lateral regions of the equine third metacarpal bone were fractured in four point bending by monotonic loading to failure under deflection …

Physical Metallurgy: Providing Unifying Principles In Diverse Areas Of Materials Engineering, Katherine C. Chen, Vilupanur A. Ravi

Materials Engineering

No abstract provided.

Structural And Diffusional Effects Of Hydrogen In Tini, Alan R. Pelton, Christine Trépanier, Xiao-Yan Gong, Andreas Wick, Katherine C. Chen

Materials Engineering

Hydrogen can be inadvertently added to Nitinol medical devices through electropolishing, caustic cleaning, or exposure to other acidic or basic solutions. Moderately high hydrogen concentrations can lead to embrittlement characterized by lowered ductility and changes in transformation behavior. The purpose of the present report is to discuss recent results on the effects of hydrogen in annealed TiNi. Samples are charged with hydrogen and analyzed with x-ray diffraction; these data indicate that even relatively small amounts of hydrogen can affect the crystal structure. Additions of up to 1000 wppm hydrogen increase the atomic volume by more than 2%, decrease peak intensity …

Cpt-Based Liquefaction Field Case Histories From The 1995 Hyogoken-Nambu (Kobe) Earthquake, Japan, Y. Suzuki, Kohji Tokimatsu, Robb E.S. Moss, Raymond B. Seed, Robert E. Kayen

Civil and Environmental Engineering

This report documents CPT-based field case histories from the 1995 Hyogoken-Nambu (Kobe) Earthquake in Japan. These case histories are proprietary and were acquired by Mr. Y. Suzuki of the Kajima Corporation under the supervision of Prof. K. Tokimatsu of Tokyo Institute of Technology. Each case history is composed of two pages, one page of vital statistics and one page showing the CPT trace with the assumed critical layer delineated. Field performance of each site was assessed by Mr. Y. Suzuki as well as the performance assessments published in Akai et al. (1995). The liquefaction and non-liquefaction data that were used …

Recent Advances In Soil Liquefaction Engineering: A Unified And Consistent Framework, Raymond B. Seed, K. Onder Cetin, Robb E.S. Moss, Annie M. Kammerer, Jiaer Wu, Juan M. Pestana, Michael F. Riemer, Rodolfo B. Sancio, Jonathan D. Bray, Robert E. Kayen, Allison Faris

Civil and Environmental Engineering

Over the past decade, major advances have occurred in both understanding and practice with regard to assessment and mitigation of hazard associated with seismically induced soil liquefaction. Soil liquefaction engineering has evolved into a sub-field in its own right, and engineering assessment and mitigation of seismic soil liquefaction hazard is increasingly well addressed in both research and practice. This rapid evolution in the treatment of liquefaction has been pushed largely by a confluence of lessons and data provided by a series of major earthquakes over the past dozen years, as well as by the research and professional/political will engendered by …

Complex Low-Pass Filters, Peter Kiss, Vladimir I. Prodanov, Jack Glas

Electrical Engineering

Zero-if transceivers suffer from the imbalance of the I and Q paths. By using a complex low-pass filter topology instead of a conventional pair of real low-pass filters, this imperfection can be reduced. Both analytical and numerical analysis show that the proposed technique is significantly more robust to circuit imperfections than the traditional architecture.

A Growth Mixture Theory For Cartilage With Application To Growth-Related Experiments On Cartilage Explants, Stephen M. Klisch, Silvia S. Chen, Robert L. Sah, Anne Hoger

Mechanical Engineering

In this paper, we present a growth mixture model for cartilage. The main features of this model are illustrated in a simple equilibrium boundary-value problem that is chosen to illustrate how a mechanical theory of cartilage growth may be applied to growth-related experiments on cartilage explants. The cartilage growth mixture model describes the independent growth of the proteoglycan and collagen constituents due to volumetric mass deposition, which leads to the remodeling of the composition and the mechanical properties of the solid matrix. The model developed here also describes how the material constants of the collagen constituent depend on a scalar …

Statistics Of Single-Degree-Of-Freedom Estimate Of Displacement For Pushover Analysis Of Buildings, Anil K. Chopra, Rakesh K. Goel, Chatpan Chintanapakdee

Civil and Environmental Engineering

Investigated is the basic premise that the roof displacement of a multistory building can be determined from the deformation of a single-degree-of-freedom (SDF) system. The responses of both systems are determined rigorously by nonlinear response history analysis, without introducing any of the approximations underlying the simplified methods for estimating the deformation of a SDF system (see, e.g., FEMA-273 or ATC-40 guidelines). The statistics of the SDF system estimate of roof displacement are presented for a variety of generic frames and six SAC buildings subjected to ground motion ensembles. Data obtained for generic frames indicate that the first ‘‘mode’’ SDF system …

Chemigation And Fertigation Basics For California, Charles M. Burt

BioResource and Agricultural Engineering

Chemigation is the application of any chemical through an irrigation system. Examples of chemicals include insecticides, fungicides, fertilizers, water amendments, soil amendments, and compounds used to reduce plugging of drip emitters. Proper chemigation reduces energy consumption (less fertilizer, chemicals, and tractor travel) and improves crop quality and yields.

Fertigation accounts for the majority of chemigation. The sophistication of fertigation knowledge and practices is at about the same level as drip/microirrigation was in the mid-1970s. A lot of equipment and chemicals exist, and many farmers use fertigation, but only a relatively small percentage of those farmers are sophisticated users.

Strategies For Improving Neural Signal Detection Using A Neural-Electronic Interface, Robert B. Szlavik

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. From both a theoretical and experimental perspective, these studies have emphasized the variability in the characteristics of the detected action potential from the nerve cell. The demonstrated lack of reproducible fidelity of the nerve cell action potential at the device junction would make it impractical to implement these devices in any neural prosthetic application where reliable detection of the action potential was a prerequisite. In this study, the effects of several different physical parameters on the …

Package Performance Testing Of Dangerous Goods In High Altitude Shipments, S. Paul Singh, Gary J. Burgess, Jay A. Singh

Industrial Technology and Packaging

This paper discusses the impact of high altitude shipments on package integrity. High altitude shipments are encountered when trucks travel over high mountain passes or when cargo and feeder aircraft transport packages in non-pressurized or partially-pressurized cargo holds. Both these types of transport methods will result in severe changes in pressure and temperature conditions as compared to packages being transported close to sea-level The testing of packages under these conditions is critical since package integrity may be compromised. The current shipping tests performed in test labs do not account for pressure changes and vibration together. This study showed that combination …

Body Concept Design For Pedestrian Head Impact, S. Iskander Farooq, Peter J. Schuster

Mechanical Engineering

In 1996, the European Enhanced Vehicle Safety Committee, Working Group 17 (EEVC WG17) proposed -a set of impact procedures to evaluate the pedestrian injury risk of vehicle fronts. These procedures address three aspects of pedestrian protection -head impacts, lower limb impacts, and thigh impacts -through vehicle subsystem tests. The criteria assessed during these impact tests are affected by the design of most parts of the vehicle body front-end.

One of the challenges to vehicle design introduced by these tests is the impact of an adult pedestrian headform to the top of the fender. The proposed acceptance level for Head Injury …

Computational Simulation And Piv Measurements Of The Laminar Vortical Flowfield For A Delta Wing At High Angle Of Attack, Russell M. Cummings, Scott A. Morton, Stefan G. Siegel

Aerospace Engineering

The low-speed, laminar flowfield for a 70°-sweep delta wing is investigated. Solutions to the unsteady, three-dimensional, compressible Navier-Stokes equations were obtained on an unstructured grid to match results from an experiment performed in a water tunnel. The experiment was conducted with the delta wing at an angle of attack of 35° and the freestream flow at a root-chord Reynolds number of 40,700. The computational results are analyzed and compared with the experimental results in order to show how computations and experiments can be conducted in a synergistic fashion. Details about the primary vortex location, vortex burst, secondary vortex, and shear …

Des Grid Resolution Issues For Vortical Flows On A Delta Wing And An F-18c, Scott A. Morton, Mathew B. Steenman, Russell M. Cummings, James R. Forsythe

Aerospace Engineering

An assessment of unstructured grids for use in Detached-Eddy Simulations (DES) of vortical flowfields over two configurations, a 70 degree delta wing and an F-18C are presented. The role of the grid in detached eddy simulations of vortical flowfields, including complex features such as vortex breakdown, is assessed on a delta wing with comparison to wind tunnel data. Adaptive mesh refinement is applied to the delta wing grid to improve the focus region aft of the vortex breakdown where massively separated flow exists and unsteady pressures are generated that could impact the loads on vertical tails of more complex configurations. …

A Multifaceted Approach To The Aiaa Foundation Undergraduate Team Aircraft Design Competition, Russell M. Cummings, Aaron R. Byerley

Aerospace Engineering

A multifaceted, novel approach was used to help students create entries for the AIAA Foundation Undergraduate Team Aircraft Design Competition. Each entry involved the design, analysis, construction, and testing of the aircraft. Three groups were involved for each airplane: the first group was responsible for the airframe, the second group was responsible for the engine, and the third group was responsible for the construction and flight testing of a radio-controlled flying model. There was an overall Chief Executive Officer who insured that engine-airframe integration issues were addressed. Students from a variety of majors, both technical and non-technical, participated in various …