Engineering Commons^™

Automated State Model Generation Algorithm For Power Circuits And Systems, O. Wasynczuk, Scott D. Sudhoff

Electrical and Computer Engineering Faculty Research & Creative Works

A new approach of automatically generating state-space models of power circuits and systems is presented. In this approach, the composite system state equations are established algorithmically given the standard node incidence matrix and elementary branch data (e.g. resistances, inductances, back emf's). The resulting state equations can be solved using a variety of numerical techniques or commercially available computer simulation programs. An example system consisting of a three-phase generator and rectifier load is used to illustrate this approach. Experimental verification is also provided. © 1996 IEEE.

A Voltage Control Strategy For Current-Regulated Pwm Inverters, Oleg Wasynczuk, Scott D. Sudhoff, Tin D. Tran, David H. Clayton, Henry J. Hegner

Electrical and Computer Engineering Faculty Research & Creative Works

Alternative voltage control strategies for current-regulated PWM inverters are analyzed, including previously established feedforward and feedforward/feedback controllers and a newly proposed decoupling feedback control strategy. The steady-state and dynamic characteristics of each of these control methods are illustrated and compared for a selected inverter design. It is shown that the feedforward controller exhibits steady-state error and an undesirable overshoot of the output voltages during startup. The addition of a feedback loop eliminates the steady-state error and reduces the overshoot; however, the natural response is underdamped regardless of the choice of feedback gains. A decoupling feedback control strategy that eliminates the …

A Cultural Resource Investigation Of Two Louisiana-Pacific Corporation Parcels, Susie Van Kirk

Susie Van Kirk Papers

During the month of October, November, and December 1996, a Cultural Resources Investigation was conducted on two Louisiana-Pacific Corporation parcels located at Big Lagoon, Humboldt County, California (see Map 1). The survey was requested by Jamie Heltsley of Ron Hunt Surveying & Forestry, Arcata, California. Proposed project plans include the combining of four separate assessors parcels into two assessor's parcels.

The purposes of this investigation were to (1) locate and record project area cultural resources; (2) to evaluate the significance of study area cultural resources; (3) to assess potential impacts to cultural resources resulting from project related operations; (4) to …

Magnetic Dynamics In Underdoped Yba₂Cu₃O₇₋ₓ: Direct Observation Of A Superconducting Gap, Pengcheng Dai, Mohana Yethiraj, Herbert A. Mook, Terrence B. Lindemer, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Polarized and unpolarized triple-axis neutron measurements were performed on an underdoped crystal of YBa₂Cu₃O_7-x (x = 0.4 ± 0.02, T_c = 62.7 K). Our results indicate, contrary to earlier evidence, that the spin excitations in the superconducting state are essentially the same as those in the fully doped material except that the unusual 41 meV resonance is observed at 34.8 meV. The normal state spin excitations are characterized by a weakly energy-dependent continuum whose temperature dependence shows the clear signature of a superconducting gap at T_c. The enhancement at the resonance is …

A Specialization Toolkit To Increase The Diversity Of Operating Systems, Calton Pu, Andrew P. Black, Crispin Cowan, Jonathan Walpole, Charles Consel

Computer Science Faculty Publications and Presentations

Virus and worm attacks that exploit system implementation details can be countered with a diversified set of implementations. Furthermore, immune systems show that attacks from previously unknown organisms require effective dynamic response. In the Synthetix project, we have been developing a specialization toolkit to improve the performance of operating system kernels. The toolkit helps programmers generate and manage diverse specialized implementations of software modules. The Tempo-C specializer tool generates different versions for both compile-time and run-time specialization. We are now adapting the toolkit to improve operating system survivability against implementations attacks.

Controlling Three-Axis Attitude Rates On A Pointing System Using Nonlinear Observer And Two Axis Measurements, Marcelo C. Algrain

Department of Electrical and Computer Engineering: Faculty Publications

A new observer design method that allows for estimating the angular rates along a vehicle’s three principal axes is described. The observer uses measurements from a single two-axis angular rate sensor (gyro) and determines the rates for the third axis using a nonlinear observer. Unlike conventional approaches where the equations governing vehicle motion (Euler’s equations) are linearized and then an observer is constructed based on the linear model, this method does not require linearization of the system. Instead, a pseudo-linear representation is used. The pseudo-linear model is obtained by systematically decomposing a nonlinear system into linear and nonlinear terms. The …

Modern Water Control And Management Practices In Irrigation: Methodoloy And Criteria For Evaluating The Impact On Performance, Charles M. Burt

BioResource and Agricultural Engineering

No abstract provided.

Temporal Gis Applications In Public Transit Planning And Management, Hesham R. Elbadrawi

FIU Electronic Theses and Dissertations

Geographic Information Systems (GISs) provide a powerful framework for various tasks of transit management such as planning, performance evaluation, and marketing. GIS may be used to solve complex planning problems, assist in operations planning, and meet other management and operational needs. However, due to the changing nature of transit planning and operational data, transit planners and operators need to analyze the data over time, which requires a temporal GIS that is capable of storing, manipulating, and analyzing changes with respect to both time and space.

Temporal GIS will allow planners and transit operators to analyze data within a certain time …

Preliminary Evaluation Of The Effects Of A Pumping Well On Existing Surface Water Resources Located In T. 12n, R. 2e, Sec. 23, Cache And Box Elder Counties, Denny J. Johnson, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This report contains the results of a preliminary study of the impact of pumping a well located in T. 12N, R. 2E, sec. 23, Cache and Box Elder Counties, Utah. A semianalytical capture zone analysis was performed to determine if pumping at the well is likely to reduce flow in Willow Creek or any of three springs in the surrounding area. The well has been used from 1974 to present and is sometimes pumped at 90 gallons per minute (gpm) (verbal communication, Veibell, 1996).

Dynamics Of An Adsorbed Patch And A Model For Spreading Of Films Of Ultralow Thicknesses, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

The dynamics of ultrathin films of liquids with vanishing 3D volatility, on solid surfaces, has been modeled by assuming that the films can be taken to be adsorbed patches spreading under surface diffusion. when the phase behavior of the adsorbed films is taken into account, it is seen that a vapor patch will spread without limits and evolve into a Gaussian profile. For a liquid film which has low 2D volatility, a patch will appear to equilibrate and the surface ahead will remain dry. This is the "pancake," a case where a wetting liquid stops spreading. the spreading kinetics is …

Application Of Inversions To Lossless Image Compression, Ziya Arnavut

Department of Electrical and Computer Engineering: Faculty Publications

Linear prediction schemes, such as that of the Joint Photographic Experts Group (JPEG), are simple and normally produces a residual sequence with lower zero-order entropy. Occasionally the entropy of the prediction error becomes greater than that of the original image. Such situations frequently occur when the image data have discrete gray levels located within certain intervals. To alleviate this problem, various authors have suggested different preprocessing methods. However, the techniques reported require two passes. We extend the definition of Lehmer-type inversions (Lehmer 1960 and 1964) from permutations to multiset permutations and present a one-pass algorithm based on inversions of a …

Arts, Computers And Artificial Intelligence, Sol Neeman Ph.D.

Engineering Studies Faculty Publications and Creative Works

Science and art seem to belong to different cultures. Science and technology, mainly the products of the intellect, use terminology and vocabulary that are concise and well defined. In contrast, in artistic expression, ambiguity is a powerful component. Still the relationship between these two different categories of human activity is interesting and fascinating. In this paper, a general comparison of these two disciplines will be introduced. Then the possibility of mechanical creation of art using computers and artificial intelligence will be discussed. This will be followed by two techniques which are used to create poetry and music. First, a statistical …

Preparing The Leaders For Mechatronics Education, Sema E. Alptekin

Industrial and Manufacturing Engineering

Mechatronics is the synergetic combination of precision mechanical engineering, electronic control and systems thinking in the design of products and processes. There is a need to develop interdisciplinary programs in Mechatronics that better prepare our graduates to design, build, and operate the products and systems of today and tomorrow. To address this need, National Science Foundation funded a project entitled "Preparing the Leaders for Mechatronics Education" undertaken by Cal Poly in 1995 - 1996. In this paper, the activities that took place during this two-year program is outlined. Several courses and course modules have already been developed and implemented by …

Development Of Outcome Assessments At Wpi, William W. Durgin, Lance Schachterle

Office of the Provost Scholarship

The WPl PLAN, adopted by the WPl faculty in 1970, strongly anticipates current thinking about student outcomes assessments by structuring degree requirements that mandate that students demonstrate their ability to perform professional functions embodied in ABET Criteria 2000, especially Criteria 3 and 4. The WPI faculty has also practiced both student and self evaluations of these outcomes through respectively grades and peer review (both departmental and campus-wide) of student performance.

Polymer Science In Croatia, Otto Vogl, Franjo Flajsman, Zvonomir Janovic, Helena Jasna Mencer

Emeritus Faculty Author Gallery

No abstract provided.

46. Milan Lazar, Otto Vogl, Lyda Rychla

Emeritus Faculty Author Gallery

No abstract provided.

International Symposium On Ionic Polymerization, Istanbul, Turkey, Otto Vogl, Yusuf Yagci

Emeritus Faculty Author Gallery

No abstract provided.

Distributed Activation Energy Model Of Heterogeneous Coal Ignition, John C. Chen

Mechanical Engineering

We present a model that simulates the conventional tube-furnace experiment used for ignition studies. The Distributed Activation Energy Model of Ignition accounts for particle-to-particle variations in reactivity by having a single preexponential factor and a Gaussian distribution of activation energies among the particles. The results show that the model captures the key experimental observations, namely, the linear increase in ignition frequency with increasing gas temperature and the variation of the slope of the ignition frequency with oxygen concentration. The article also shows that adjustments to the model parameters permit a good fit with experimental data.

Row Crop Drip Irrigation On Peppers Study, Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

High Rise Farms, located just north of Morgan Hill installed a new buried row crop drip irrigation system in 1993. The amount of the CEC loan was $42,700.

The installation of the drip irrigation system on the Peppers did provide significant improvements in the amount of water use, energy required and yield increases especially in the first year of operation (1993) and the third year of operation (1995). The second year of the project (1994) did not have yield increases. The primary lessons learned from this project included:

• The yield differential between drip and the furrow irrigation methods was attributed …

Row Crop Drip Irrigation On Bell Peppers Study, Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

Underwood Ranches, located near Oxnard, installed a buried drip system on 50 acres of peppers in 1993. The amount of the CEC loan was $50,000.

The buried drip system provided sufficient advantages in water management, energy savings, and yield increases to convince the farm to expand its drip acreage to 140 acres in June 1995, and 320 acres in Sept. 1996. The farmer was an ideal cooperator.

The primary lessons learned on this project were:

• A grower needs approximately two years of experience and technical assistance in order to feel comfortable with a buried drip system. Even after that time, …

Random Response To Periodic Excitation With Correlated Disturbances, Zhikun Hou, Yunshen Zhou, Mikhail F. Dimentberg, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

The paper addresses non-Gaussian stationary response of linear single-degree-of-freedom (SnOF) systems subject to a periodic excitation with correlated random amplitude and phase disturbances that are modeled as correlated Gaussian white noise processes. Correlation between amplitude and phase modulation is specified by the cross-correlation coefficient. Numerical results for the second and fourth moment responses are presented. The probability density function of the response is calculated based on the cumulant-neglect closure method. Non-Gaussian nature of the response is discussed in terms of the excess factor. The results show that the moment responses generally increase with larger random amplitude disturbance and may decrease …

Oxygen Plasma Asher Contamination: An Analysis Of Sources And Remedies, R. A. Synowicki, Jeffrey S. Hale, William A. Mcgahan, Natale J. Ianno, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

The low Earth orbit (LEO) environment is commonly simulated using oxygen plasma ashers to determine the effects of LEO on spacecraft materials. However, plasma ashers can also contaminate samples during plasma exposure, making them less than ideal for space simulation. This study results from attempts to minimize or eliminate contamination. Optical methods of variable angle spectroscopic ellipsometry and reflectance spectrophotometry were used to quantify contaminant stoichiometry and deposition rate. Auger electron spectroscopy identified deposited contaminants and their surface coverage. Contamination results from etching of the rubber chamber seals by the plasma. The deposited contaminant was nearly indistinguishable from fully stoichiometric …

Acuta Enews November 1996, Vol. 25, No. 11

ACUTA Newsletters

In This Issue

Univ. of Idaho: Homepage Sweet Homepage

Institutional Excellence Award

Committee Member Approved

More Angles for 809 Fraud

Welcome New Members

President's Message

The '90s: New Challenges for Telecom

DC at a Glance

Campus News Briefs

Industry Insights

Mechanisms Of Cytokine-Mediated Localized Immunoprotection., Nora Sarvetnick

Journal Articles: Regenerative Medicine

No abstract provided.

Strength Of Flexural Members Using Structural Grade 80 Of A653 Steel (Deck Panel Tests), Shaojie Wu, Wei-Wen Yu, Roger A. Laboube

CCFSS Library (1939 - present)

This second progress report describes the design of deck panel specimens for flexural tests and presents the test results of ninety-three deck panel specimens. The deck panels consisted of single and multiple hat-shaped ribs in their cross sections and were manufactured from 28, 26, and 22 gage steel sheets of Structural Grade 80 of ASTM A653 Steel. Among the ninety-three deck panel specimens, seventy-two panels were tested in simply supported and two-point loading conditions; sixteen panels were tested in simply supported and one-point loading conditions; and five panels with screws penetrating through tension flanges were tested in simply supported and …

A Real-Time Self-Tuning Web Tension Regulation Scheme, Brian T. Boulter, Zhiqiang Gao

Electrical and Computer Engineering Faculty Publications

A self-tuning control scheme is proposed for tension regulation in a web transport system. A computationally efficient self-tuning method is first described. The frequency domain model of the plant is then described. Simulations of the on-line tuning are presented. The paper closes with a discussion of cognizant real-time implementation issues.

Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling

Faculty Publications

Energy dispersive spectrometry line scan and ac impedance spectroscopy were used in this study to investigate the chemical reactions between two cathode materials, La_0.84Sr_0.16MnO₃ (LSM), La_0.5Sr_0.5CoO_3-δ (LSC), and the electrolyte La_0.9Sr_0.1Ga_0.8Mg_0.2O_2.85 (LSGM). Significant interdiffusions of Co into LSGM and Ga into LSC were found at an LSC/LSGM interface even at relatively low fabrication temperatures. In contrast, only small interdiffusions of Mn into LSGM and Ga into LSM were detected at the LSM/LSGM interface even though it was fired at 1470°C. The …

Wear And Friction Behavior Of Metal Impregnated Microporous Carbon Composites, Gultekin Goller, D. P. Koty, Surendra N. Tewari, M. Singh, A. Tekin

Chemical & Biomedical Engineering Faculty Publications

Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the …

Permeability Of Microporous Carbon Preforms, S. K. Datta, N. Simhai, Surendra N. Tewari, Jorge E. Gatica, M. Singh

Chemical & Biomedical Engineering Faculty Publications

The permeability of microporous amorphous carbon preforms with varying pore size and pore distributions has been experimentally examined. The porous structures have been characterized by mercury porosimetry and by quantitative metallography of pressure-infiltration-cast metal matrix composites based on the carbon preforms. The permeability shows a linear correlation with the fraction porosity and the square of the pore diameter.

On Hack's Law, Riccardo Rigon, Ignacio Rodriguez-Iturbe, Amos Maritan, Achille Giacometti, David G. Tarboton, Andrea Rinaldo

Civil and Environmental Engineering Faculty Publications

Hack's law is reviewed, emphasizing its implications for the elongation of river basins as well as its connections with their fractal characteristics. The relation between Hack's law and the internal structure of river basins is investigated experimentally through digital elevation models. It is found that Hack's exponent, elongation, and some relevant fractal characters are closely related. The self-affine character of basin boundaries is shown to be connected to the power law decay of the probability of total contributing areas at any link and to Hack's law. An explanation for Hack's law is derived from scaling arguments. From the results we …