Engineering Commons^™

Developing A Convective Code With Vorticity Transport In Upwind Method, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The Navier-Strokes equations are usually used to solve the convective problems, however, to satisfy the conversation of mass, the uncertainty of pressure terms will easily trigger off the numerical divergence during the iterative process; which results in a calculating failure and makes the numerical solutions impossible. In this study, a vorticity–transport method that avoids the involvement of pressure terms by cross differentiate the governing equations and meets the flow conservation with stream function was proposed. With the aid of the upwind scheme and implicit method, an effective transformation from the partial differential equations into the vortex potential algebraic equations would …

Multi-Objective Control Design For Stochastic Large-Scale Systems Based On Lmi Approach And Sliding Mode Control Concept, Koan-Yuh Chang, Wen-Jer Chang

Journal of Marine Science and Technology–Taiwan

In this paper, a controller u (t) i is designed for stochastic large-scale systems to achieve the following three objectives simultaneously: the pole placement constraint, H∞ norm constraint and individual state variance constraint. In terms of the invariance property of sliding mode control, both the uncertain interconnection terms and an unknown nonlinear function will disappear on the sliding mode. Then, with the aid of upper bound covariance control theory, pole placement skill and H∞ norm control theory, a controller, in which the control feedback gain matrix Gi is synthesized using linear matrix inequality approach, is derived to achieve the above …

Effect Of Steel Fiber On The Mechanical Properties Of Cement-Based Composites Containing Silica Fume, Wei-Ting Lin, Ran Huang, Chin-Lai Lee, Hui-Mi Hsu

Journal of Marine Science and Technology–Taiwan

An experimental program was carried out to evaluate the mechanical properties of cement-based composites. Test variables included water to cementitious ratio, dosage of silica fume and volume fraction of steel fiber. Compressive strength test, direct tensile strength test, splitting tensile strength test, abrasion resistance test and drop weight test were performed and the results were analyzed statistically. According to the results of this study, the designed direct tensile testing method was a suitable method to estimate the tensile strength of fiber cement-based composites. Addition of fibers provided better performance for the cement-based composites, while silica fume in the composites would …

Characteristic Study Of Mhd Minipump, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The present study aims to develop and discuss the availability of the Magneto Hydrodynamics Minipump (MHD) as a miniaturizative part specified for precise manufacturing or medical application. Based on the MHD theory, an available working current (1.8A) induced by lower voltage (0-12V) and weaker magnetic intensity (0.04T) meets the need in mini-system operation. However, precise estimations of working capacity, maximum head, dynamic head, and static head in various electrolyte concentrations are necessary. Furthermore, this work also provides a simplified analytic model with a static balance between Lorentz force, surface tension force, and body force. Compared with analytic solutions and experimental …

Survey Of Hardware Platforms For An Energy Efficient Implementation Of Matching Pursuits Algorithm For Shallow Water Networks, Bridget Benson, Ali Irturk, Junguk Cho, Ryan Kastner

Electrical Engineering

Coral reefs worldwide are in serious decline. Underwater wireless sensor networks may be the answer to providing the persistent monitoring presence needed to obtain the data necessary to better understand how to protect these ecosystems for the future. Many advances have been made in underwater acoustic communication devices for underwater wireless sensor networks, but a major challenge that still remains is obtaining an energy efficient modem design. To begin to address this challenge, we implement the Matching Pursuits algorithm for channel estimation, an energy consuming portion of an existing underwater acoustic modem designed for shallow water networks, on a variety …

Pylon Effects On A Scramjet Cavity Flameholder Flowfield, Andrew B. Freeborn

Theses and Dissertations

Cavity flameholders in supersonic combustion ramjet (scramjet) combustors, while effective, fail to take advantage of the full combustor volume. Adding a pylon to the leading edge of a cavity flameholder generates a flowfield increasing mass exchange between the cavity and main combustor flow, increasing the mixing interface between flameholder products and main combustor flow, and exhibiting minimal Reynolds number effects. To demonstrate this modified flowfield driven by supersonic expansion behind the pylon, pylon-cavity flameholder flowfield data were obtained through a combination of wind tunnel experimentation and steady-state computational fluid dynamics (CFD). Flowfield effects of the pylon-cavity were examined at a …

In-Line Broadband 270 Degrees (3 Lambda/4) Chevron Four-Reflection Wave Retarders, R. M.A. Azzam, H. K. Khanfar

Electrical Engineering Faculty Publications

The net differential phase shift Δ_t introduced between the orthogonal p and s linear polarizations after four successive total internal reflections inside an in-line chevron dual-Fresnel-rhomb retarder is a function of the first internal angle of incidence φ and prism refractive index n. Retardance of 3λ/4 (i.e., Δ_t=270°) is achieved with minimum angular sensitivity when φ=45° and n=1.900822. Several optical glasses with this refractive index are identified. For Schott glass SF66 the deviation of Δ_t from 270° is ≤4° over a wavelength range of 0.55≤λ≤1.1 μm in the visible and …

Ceas E-News 09.09.2008, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

CEAS students collect nursing data for Bronson study

Strain Sensitive Coax Cable Sensors For Monitoring Structures, Genda Chen, James L. Drewniak, Huimin Mu, David Pommerenke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The invention provides increased structural monitoring systems that have sensitive continuous coaxial cable sensors. A preferred embodiment sensor cable of the invention includes an inner conductor, a dielectric jacket, and an outer conductor that is configured to passively deform responsively to strain in an associated structure. The deformation can be aided by the physical structure of the dielectric jacket, the outer conductor, or a combination of both. The deformation translates strain into a measurable change in a reflection coefficient associated with the outer conductor.

Hypermixer Pylon Fuel Injection For Scramjet Combustors, Jason C. Doster

Theses and Dissertations

Fueling the core airflow of a circular or elliptical scramjet combustor cross-section often requires intrusive geometries. Intrusive geometries can distribute the fuel evenly across the combustor cross-section and act as a flameholder for the fuel/air mixture. Compared to conventional transverse or angled wall injection, intrusive geometries allow easier penetration into the core combustor airflow and reduced fuel injection pressures. The design and testing of an intrusive pylon geometry for scramjet combustor fueling is the subject of this research. Three pylon configurations are compared: a basic pylon, a ramp pylon, and an alternating wedge pylon. All three pylon configurations exhibit the …

Improved Contact For Thermal And Electrical Transport In Carbon Nanofiber Interconnects, Tsutomu Saito, Toshishige Yamada, Drazen Fabris, Hirohiko Kitsuki, Patrick Wilhite, Makoto Suzuki, Cary Y. Yang

Electrical and Computer Engineering

We study the performance and reliability of carbon nanofiber (CNF) interconnects under high-current stress by examining CNF breakdown for four test configurations, suspended/supported with/without tungsten deposition. The use of W is to improve the CNF-electrode contact. The supported cases show a larger current density just before breakdown than the suspended ones, suggesting an effective heat dissipation to the substrate. The W-deposited contacts reduce the initial total resistance from megaohm range without W to kilo-ohms. High-current stress does not change the total resistance of the test structures with W unlike those without W deposition.

Preparation & Accreditation Of Level 7 Engineering Programmes, Mark Mcgrath

Conference Papers

Accreditation of 3rd level educational programmes by a suitably recognised professional body is of particular relevance in relation to engineering. The completion of a sequence of modules which leads to the attainment of this professionally recognised award is viewed as integral to the undertaking. The engineering technology fields are developing and expanding rapidly and the third level sector must keep abreast of these changes. This is essential if the third level institutions wish to continue delivering programmes which produce graduates who can successfully complete the transition from 3rd level to the various engineering sectors. This paper outlines various aspects of …

2008 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Fall 2008 semester ENGR333 project assessed the feasibility of a Green Revolving Fund for Calvin College. I asked the students “What would it take to implement a Calvin Energy Efficiency Fund (CEEF)?”

The project emerged from the work of the previous year’s students who uncovered the concept of green revolving funds.

Immediately after the Fall 2008 semester, I went on sabbatical to South Africa for all of 2009. While I was away, the Calvin administration established the Calvin Energy Recovery Fund (CERF). Over the next decade, CERF saved hundreds of thousands of dollars in energy costs and was …

Application Of The Modified Log-Wake Law In Open-Channels, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

The modified log-wake law, which was developed for turbulent boundary layers and pipe flows, is extended to turbulent flows in open-channels. Turbulent velocity profiles in open-channels can be approximated with three components: (1) the law of the wall that results from the constant bed shear stress; (2) the law of the wake that reflects the effects of gravity, secondary currents and bed roughness; and (3) the cubic correction near the maximum velocity. A procedure to determine the four model parameters from velocity measurements while keeping κ = 0.41 is presented. The modified log-wake law compares very well with experimental data …

A Novel Method Characterizing The Impact Response Of Functionally Graded Plates, Reid A. Larson

Theses and Dissertations

Functionally graded material (FGM) plates are advanced composites with properties that vary continuously through the thickness of the plate. Metal-ceramic FGM plates have been proposed for use in thermal protection systems where a metal-rich interior surface of the plate gradually transitions to a ceramic-rich exterior surface of the plate. The ability of FGMs to resist impact loads must be demonstrated before using them in high-temperature environments in service. This dissertation presents a novel technique by which the impact response of FGM plates is characterized for low-velocity, low- to medium-energy impact loads. An experiment was designed where strain histories in FGM …

Spatial Variability Of Waste Temperatures In Msw Landfills, James L. Hanson, Nazli Yesiller, Nicolas K. Oettle

Civil and Environmental Engineering

Spatial variability of waste temperatures in MSW landfills was determined over different physical and temporal scales. Data have been obtained at four landfills located in different climatic regions in North America: Alaska, British Columbia, Michigan, and New Mexico. Temperatures were measured using 100 to over 250 sensors at each site. Data were obtained for 5 to 10 year periods at the sites. Temperatures were measured in wastes with a broad range of ages: newly-placed and old (up to 40-year old). The characteristic shape of waste temperature vs. depth relationships consists of a convex temperature profile with maximum temperatures observed at …

Experimental Determination Of Cover Surface Temperature Functions At Msw Landfills, Nicolas K. Oettle, James L. Hanson, Nazli Yesiller

Civil and Environmental Engineering

Cover temperatures were measured at four MSW landfills located in different climatic regions in North America: Michigan, New Mexico, Alaska, and British Columbia. Temperature measurements were made on a weekly basis throughout the depth of the cover profiles extending from the surface into the top layers of the underlying wastes. Bias was produced in the surface temperature data due to the combined effects of the time of day that weekly surface measurements were taken and the high diurnal variations at the surface. Analytical methods were used to obtain representative surface temperature functions for the covers from experimental data. Mean cover …

Control Of Double Fed Induction Generator Wind Turbine During Network Voltage Unbalance Conditions, Joseph Kearney, Michael Conlon

Conference papers

The behaviour of Double-Fed Induction Generators to supply network voltage unbalance is investigated. The paper describes a method to control the rotor-side converter in a DFIG when subjected to the effects of network voltage unbalance conditions. A parallel control scheme is implemented to control the positive and negative sequence components independently. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque oscillations and a reduction in the high unbalanced currents generated as a result of the applied voltage unbalance.

Watershed Management And Water Production Study For State Of Utah, Ibrahim Nourein Mohammed, David G. Tarboton

Civil and Environmental Engineering Faculty Publications

The amount of water produced from a watershed depends on the climate, soils, geology, land cover and land use. Precipitation water inputs in the form of rain or snow are partitioned by the watershed into evapotranspiration, runoff and groundwater recharge. This study has examined factors that may impact the production of runoff from Utah watersheds, focusing on factors related to land and watershed management. Specifically we are interested in how land use changes, such as afforestation, deforestation, agricultural, urban, industrial and mining development, impact runoff. The scale of interest is regional subbasins at the USGS cataloging unit 8 digit Hydrologic …

Ceas E-News 09.02.2008, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

HP grant for tablet PCs to provide virtual materials science lab

Modeling Of Space-Charge-Limited Current Injection Incorporating An Advanced Model Of The Poole-Frenkel Effect, Satoshi Takeshita

All Theses

The current flow due to Space-Charge-Limited (SCL) emission is well known and the associated current-voltage power law relationship can be observed in many materials, particularly in insulators and semiconductors. Under an applied field, the space-charge effect occurs due to the carrier injection, and the resulting current due to the presence of the space-charge effect is referred to as SCL current. In the SCL current theory, the presence of localized traps in a material has a significant effect on the transport of injected carriers; however, in the first order SCL model, the trap barrier height is assumed to be constant for …

Avoiding Common Problems With Drip Tape, Charles M. Burt

BioResource and Agricultural Engineering

This publication is meant to help farmers, dealers, and manufacturers recognize and understand some of the problems that have been experienced with drip tape – problems that are quite different from manufacturing defects. Problems that are quickly detected and properly identified can often be remedied, or be avoided in the future. The report addresses drip tape damage caused by pests, installation, emitter pressure, plugging, and other categories.

Response To Changes In Key Stimuli Through The Co-Evolution Of Sensor Morphology And Control, Gary Parker, Pramod J. Nathan

Computer Science Faculty Publications

Co-evolving a robot’s sensor morphology and control program increases the potential that it can effectively complete its tasks and provides a means for adapting to changes in the environment. In previous work, we presented a learning system where the angle, range, and type of sensors on a hexapod robot, along with the control program, were evolved. Although three sensor stimuli were detectable by the system, it used only two due to the relative importance of these two stimuli in completing the task. In the research presented in this paper, we used the same system, but reduced the availability of a …

Basic Control For Four Rotor Autonomous Aerial Agent, Jonathan Mclean, Gary Parker, Newell Seal

Computer Science Faculty Publications

Aerial robotics provides many practical applications in fields such as search and rescue and surveying. In order to advance the research in aerial robotics, an inexpensive test platform is required. Our four-rotor platform provides researchers with a inexpensive, fully scalable test platform for future studies. Its completely on-board processing removes the need for a virtual tether in the form of a radio transmitter, allowing for completely autonomous operation.

Evolving Predator Control Programs For A Hexapod Robot Pursuing A Prey, Gary Parker, Basar Gulcu

Computer Science Faculty Publications

Control program learning systems for autonomous robots are important to assist in their development and to allow them to adapt to changes in their capabilities and/or the environment. A common method for learning in robotics is Evolutionary Computation (EC) and a good problem to demonstrate the effectiveness of a learning system is the predator/prey problem. In previous research, we used a Cyclic Genetic Algorithm (CGA), a form of EC, to evolve the control program for a predator robot with a simple sensor configuration of 4 binary sensors, which yielded 16 possible sensor states. In this paper, we present the use …

Acuta Enews September 2008, Vol. 37, No. 9

ACUTA Newsletters

In This lssue

From ACUTA Headquarters: Ramped-up Schedule................Jeri A. Semer, CAE, Executive Director

New Section on ACUTA Website

Audio Seminar: Technology-Related lmptications of the 2008 Higher Ed Opportunities Act

Tech Talk: ACUTA Member Schools Are Mostly in the Green ........ Kevin Tanzillo, Dux PR

DC Update ......... Dave Ostrom, Washington State University

lP PBX Witt Reign: Converged PBX Will Slowly Fade Away........................Gary Audin, Delphi, lnc.

Get Your ACUTA Logo here

Look on the Light Side

lnfo Links ............. Randy Hayes, Univ. of Northern lowa

Welcome New Members

Check lt Out: RFls/RFPs, Job Postings, Press Releases

Reliability Analysis Of Plank Decks, Andrzej S. Nowak, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The objective of this study is to summarize the load and resistance criteria for highway bridge plank decks, and to estimate the reliability of plank decks designed by AASHTO Code. Both transverse and longitudinal planks for a variety of typical stringer spacings and plank sizes are considered. Truck traffic load data is based on the model used to calibrate the 1994 AASHTO LRFD Code. However, for plank decks, wheel load rather than whole vehicle weight is most important, and these statistics are developed for this study. For wood planks, dead load and dynamic load are not significant. The limit state …

Computational Methods For Investment Portfolio: The Use Of Fuzzy Measures And Constraint Programming For Risk Management, Tanja Magoc, Francois Modave, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

Computational intelligence techniques are very useful tools for solving problems that involve understanding, modeling, and analysis of large data sets. One of the numerous fields where computational intelligence has found an extremely important role is finance. More precisely, optimization issues of one's financial investments, to guarantee a given return, at a minimal risk, have been solved using intelligent techniques such as genetic algorithm, rule-based expert system, neural network, and support-vector machine. Even though these methods provide good and usually fast approximation of the best investment strategy, they suffer some common drawbacks including the neglect of the dependence among among criteria …

Trustmap: Towards Trust Recommendations For Maps, Paulo Pinheiro Da Silva, Nicholas Ricky Del Rio, Vladik Kreinovich, Alejandro Castaneda

Departmental Technical Reports (CS)

The web is a rich environment for exchanging spatial information. When spatial information is shared in the form of images, i.e., maps, these images almost never come with meta-information about how they were generated. This kind of meta-information is often called knowledge provenance. Access to knowledge provenance may facilitate users to make informed decisions about the quality of maps. In this paper, we propose TrustMap, a new approach for enhancing maps with trust recommendations. For a given map, TrustMap can generate recommendations from the knowledge provenance and a network of trust relations between sources of information used to derive the …

Maximum Entropy In Support Of Semantically Annotated Datasets, Paulo Pinheiro Da Silva, Vladik Kreinovich, Christian Servin

Departmental Technical Reports (CS)

One of the important problems of semantic web is checking whether two datasets describe the same quantity. The existing solution to this problem is to use these datasets' ontologies to deduce that these datasets indeed represent the same quantity. However, even when ontologies seem to confirm the identify of the two corresponding quantities, it is still possible that in reality, we deal with somewhat different quantities. A natural way to check the identity is to compare the numerical values of the measurement results: if they are close (within measurement errors), then most probably we deal with the same quantity, else …