Engineering Commons^™

Frequency Estimation Of Linear Fm Scatterometer Pulses Received By The Seawinds Calibration Ground Station, Spencer S. Haycock

Theses and Dissertations

The SeaWinds Calibration Ground Station (CGS) is a passive ground station used to receive and sample transmissions from the SeaWinds scatterometer. During post processing, the received transmissions are characterized in order to verify proper instrument operation and to eliminate error in satellite telemetry and in data products generated from processing SeaWinds data. Sources of instrument error include uncertainties in transmitted power, pulse timing, and carrier frequency drift. Identifying these errors prevents their propagation to data products. A key aspect of this analysis involves accurately estimating the parameters of the SeaWinds transmissions. As better parameter estimates are researched and developed, the …

Modeling Concrete Masonry Walls Subjected To Explosive Loads, Christopher D. Eamon, James T. Baylot, James L. O'Daniel

Civil and Environmental Engineering Faculty Research Publications

Concrete masonry unit walls subjected to blast pressure were analyzed with the finite element method, with the goal of developing a computationally-efficient and accurate model. Wall behavior can be grouped into three modes of failure, which correspond to three ranges of blast pressures. Computational results were compared to high-speed video images and debris velocities obtained from experimental data. A parametric analysis was conducted to determine the sensitivity of computed results to critical modeling values. It was found that the model has the ability to replicate experimental results with good agreement. However, it was also found that, without knowledge of actual …

Modeling And Simulation Research And Instruction At The U.S. Air Force Academy, Russell M. Cummings, Scott A. Morton, Keith Bergeron

Aerospace Engineering

Modeling and simulation has become a driving force within the engineering and science communities as the cost of, and time for, experimentation continues to rise. Some areas of study, such as chemistry and biology, may not even have the ability to fully evaluate certain processes experimentally, making modeling and simulation even more important. The situation has led many areas of research to the necessity of modeling and simulating various processes using computers. In addition, the rise in computational capabilities (the supercomputers of a decade ago are outmoded by the PC clusters of today), has led to a paradigm shift from …

Design Of Zebra Mussel Control Measures For Hydro-Electric Power Projects, G. Inci, C. J. Miller, N. Yesiller

Civil and Environmental Engineering

Zebra mussel, Dreissena polymorpha, is a biofouling organism that lives generally in freshwater ecosystems. Zebra mussel infestation has occurred at various freshwater structures and systems including raw water intakes, industrial and domestic distribution pipelines, and hydropower facilities at its native regions as well as distant locations. A study was conducted to perform risk assessment and to develop preventive measures for zebra mussel infestation at a planned hydroelectric power plant (Alpaslan II HEPP) in southeast Turkey. Zebra mussel is native to Anatolia region and existing hydropower facilities have significantly been affected by mussel infestation. The risk assessment was conducted by …

Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu

Journal of Marine Science and Technology–Taiwan

According to the Stokes micro-continuum theory, the effects of couple stresses upon the steady-state performance of wide parabolicshaped slider bearings are presented in this paper. To account for the couple stress effects arising from a Newtonian lubricant blended with various additives, the modified non-Newtonian Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. Comparing with the traditional Newtonianlubricant case, the effects of couple stresses characterized by the couple stress parameter signify an improvement in the steady-state performance. Increasing values of the couple stress parameter increases the bearing load-carrying capacity and reduces the required volume flow …

Nonlinear Dynamic Analysis Of An Orthotropic Composite Rotor Blade, Ming-Hung Hsu

Journal of Marine Science and Technology–Taiwan

This work presents the nonlinear dynamic analysis of orthotropic composite rotor blade using differential quadrature method (DQM). It can be found that the same efficient and procedure of DQM for both uniform composite beam and pre-twisted non-uniform composite beam. In this approach, only nine sample points are needed to achieve convergence. Dynamic responses of orthotropic composite rotor blade with various rotor rotation speeds are determined. Both linear and nonlinear dynamic responses have been obtained in order to study the significance of the nonlinear effect. The transient responses of the derived systems are calculated by using Newmark method. The bending-torsion coupled …

Single And Multiple Surface Scatterings From Rough Surfaces, Chin-Yuan Hsieh, Shun-Hsyung Chang

Journal of Marine Science and Technology–Taiwan

The objective of this paper is to study the contributions of multiple scattering and compare it with those of the single scattering from randomly rough surfaces. The existing Kirchhoff, small perturbation and IEM scattering model cannot be used to predict the multiple scattering along the azimuth angle. In this paper we modify the IEM model by adding the phase terms in Green’s function and its derivative for multiple scattering. The function of phase term is significant to investigate the contribution of multiple scattering in the upward and downward directions. The contribution by multiple scattering is mainly based on the normalized …

Mixed Ion-Polaron Transport In Na2o-Pbo-Fe2o3-P2o5 Glasses, A. Moguš-Milanković, A. Šantić, Signo Tadeu Dos Reis, K. Furić, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

The electrical and dielectric properties of the xNa₂O · (100 - x) · [28.3PbO · 28.7Fe₂O₃ · 43.0P₂O₅] (0 ≤ x ≤ 30) glasses were measured by impedance spectroscopy in the frequency range from 0.01 Hz to 3 MHz and the temperature range from 303 to 473 K. the conductivity for glasses containing ≤15 mol% Na₂O is predominantly electronic and is controlled by electron hopping between Fe(II) and Fe(III) ions. in these glasses the sodium ions have such a low mobility, caused by ion-polaron interaction, that they make no …

Nonlinear Rolling Motion Of Ship In Random Beam Seas, Jia-Yang Gu

Journal of Marine Science and Technology–Taiwan

The highly nonlinear roll and capsizing motion of ships in random seas are analyzed in this paper by utilizing the Melnikov function and phase space flux. Influence factors on the phase space flux, such as significant wave height, significant wave frequency, nonlinear righting arm and damping characteristic, have taken into consideration. As an example, when a fishing vessel of 30.7 m long and 6.9 m wide is considered to sail in the seas of ISSC wave spectrum, the Melnikov function in time domain is computed. Also, the relation between the phase space flux and the Melnikov function has attained and …

The Marine Single Assignment Nonstrict Hub Location Problem: Formulations And Experimental Examples, Shang-Hsing Hsieh, Hsien-Lun Wong

Journal of Marine Science and Technology–Taiwan

Marine hub-and-spoke networks have been applied to routing containerships for over two decades, but few papers have devoted their attention to these networks. The marine network problems are known as single assignment nonstrict hub location problems (SNHLPs), which deal with the optimal location of hubs and allocation of spokes to hubs in a network, allowing direct routes between some spokes. In this paper we present a satisfactory approach for solving SHNLPs. The quadratic integer profit programming consists of two-stage computational algorithms: a hub location model and a spoke allocation model. We apply a heuristic scheme based on the shortest distance …

Vibration Of Simply Supported Compound Beams To Moving Loads, Jong-Dar Yau

Journal of Marine Science and Technology–Taiwan

This paper is aimed at investigating the dynamic response of a compound beam subjected to moving loads at high speeds. The compound beam structure is composed of a simple beam and a twomember truss connected by a set of rigid bars at the midpoint of the beam. Based on the nonlinear elastic theory of a symmetric twomember truss under the action of a vertical tip load, and the incremental-iterative solution procedures for solving a nonlinear dynamic system, the dynamic response of the compound beam structure under the excitation of moving loads is studied. According to the numerical results, the nonlinear …

Turbulent Film Condensation On A Horizontal Elliptical Tube With Variable Wall Temperature, Yan-Ting Lin, Sheng-An Yang

Journal of Marine Science and Technology–Taiwan

An analytical model has been developed for the study of turbulent film condensation from downward flowing vapors onto a horizontal elliptical tube with variable wall temperature. The interfacial shear at the vapor condensate film is evaluated with the help of Colburn analogy. The condensate film flow and local/or mean heat transfer characteristics from a horizontal elliptical tube with nonuniform temperature variation under the effect of Froude number, sub-cooling parameter and system pressure parameter has been conducted. Although the non-uniform wall temperature variation has an appreciable influence on the local film flow and heat transfer; however, the dependence of mean heat …

A Hybrid Algorithm Of Evolution And Simplex Methods Applied To Global Optimization, Hsin-Chuan Kuo, Jiang-Ren Chang, Kai-Shun Shyu

Journal of Marine Science and Technology–Taiwan

In this paper, a hybrid method combining the evolution and simplex algorithms is proposed to deal with the global optimization problems of two-dimensional multi-minimum functions. Basically, the simplex method offers a search scheme without the gradient information and thus, it owns the merit of a better search speed for a local optimization problem and results in the deficiency of searching ability for the global one. In contrast, the evolution method has the better searching ability for the global problem but needs much more time. Therefore, the proposed hybrid method adopts the search technique of the simplex method and the concept …

Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang

Journal of Marine Science and Technology–Taiwan

In the present study, the atomization of a coaxial injector in the liquid/gas engine combustor was numerically investigated. Based on the wave instability analysis of the interface between liquid and gas, an atomization model for the high-speed liquid jets was established by coupling with the jet flow solutions. First, the wave instability was analyzed to predict the growth rates along the liquid jet surface by numerically solving the wave dispersion equation, while the governing equations of the liquid flow were solved for the formation of the liquid jet core and the variation of the liquid flow structure. Then, these two …

Evaluation Of Development Strategies For Kaohsiung Port Using A Goals Achievement Method, Wen-Chih Huang

Journal of Marine Science and Technology–Taiwan

The Port of Kaohsiung was the third largest container port in the world before 1999, although it dragged to sixth place by 2003. In order to increase the port’s competitiveness, this research outlines six goals and twenty-seven strategies from the viewpoint of international logistics. This research uses the goals achievement measurement for strategic planning effectiveness, and it was undertaken to develop the Goals Achievement Evaluation Model (GAEM) to cope with the problems of a large number of strategies and ambiguity in strategic definition. The GAEM uses a two-stage Delphi questionnaire by simplifying the quantity of responses on the survey. The …

An Examination Into The Statistics Of The Singular Vectors For The Multi-User Mimo Wireless Channel, Scott Nathan Gunyan

Theses and Dissertations

Many capacity and near-capacity achieving methods in multiple-input-multipleoutput (MIMO) wireless channels make use of the singular value decomposition (SVD) of the channel matrix. For the multi-user case, the SVD of the channel matrix for each user may result in right and left singular vectors that are similar between users. This proposes another descriptive characterization of the multi-user MIMO channel. Closely aligned singular vectors between any two users could reduce the achievable signaling rates of signal processing communication methods as one user would be more difficult to resolve in space-time from another. An examination into how this alignment can be described …

Electromagnetic Interference Of System On Package, Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …

Imaging Techniques And Hardware For Inhomogeneous Mri, David A. Thayer

Theses and Dissertations

Magnetic Resonance Imaging (MRI) has become one of the most important medical imaging modalities over the past few decades because of its flexibility and low risk, along with other useful attributes. For traditional MRI, the static magnetic field, B_0, must be highly homogeneous. Obtaining this homogeneity can be difficult. Traditional MRI also requires linear gradient fields that are directed along the static field direction. Under these conditions a Fourier transform relationship exists between sampled data and the image to be reconstructed. In the case of an inhomogeneous static field, gradient fields that are not linear, or gradients that are not …

Preliminary Evaluation Of Performance Enhanced Relocatable Classrooms In Three Climates, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A research project has monitored a specifically modified energy efficient portable classroom compared with a standard unit, in side-by-side installations in three states (NY, NC and FL). Energy performance data is summarized in this paper.

Scheduling Algorithms For Cioq Switches, Prashanth Pappu, Jonathan S. Turner

All Computer Science and Engineering Research

Most scalable switches are required to buffer packets at both their inputs and outputs to overcome the slow memory speeds of packet queues. This thesis deals with the design of scheduling algorithms for such Combined Input and Output Queued (CIOQ) switches. For crossbar based CIOQ switches, we demonstrate the underperformance of commercially used scheduling algorithms under overload traffic conditions using targeted stress tests and present ideas to develop robust, stress resistant versions of these algorithms that are still simple enough to be implemented in high speed switches. To regulate the flow of traffic in buffered, multi-stage switches, we introduce a …

Laser-Assisted Nanoscale Deposition Of Diamond-Like Carbon Films On Tungsten Tips, J. Shi, Yongfeng Lu, R. S. Cherukuri, K. K. Mendu, D. W. Doerr, Dennis R. Alexander, L. P. Li, X. Y. Chen

Department of Electrical and Computer Engineering: Faculty Publications

Diamond-like carbon (DLC) films were deposited on tungsten tips under KrF excimer laser irradiation in benzene solution. The deposition process was found to be highly dependent on tip sharpness. Tips with larger curvature radii and smaller aspect ratios could not be coated with DLC films under the same condition as that for sharp tips. Raman spectra showed that more sp³ tetrahedral structures were present in the DLC films on a tip with a smaller curvature radius. Simulation results showed that the tip sharpness dependent local optical enhancement played an important role in the DLC deposition process. An optical field …

Noncontact Scanning Impedance Imaging In An Aqueous Solution, Aaron R. Hawkins, Hongze Liu, Travis E. Oliphant, Stephen M. Schultz

Faculty Publications

We present a method for imaging based on noncontact electrical impedance measurements and mechanical scanning. Measurement results are shown for an initial system based on this concept. An impedance probe design is presented, applicable to the test system. Line-scan data plots of high impedance contrast structures show a good fit to a theoretical physical model. Image resolutions on the order of 100 m are indicated for the initial system. Two-dimensional impedance images of biological tissue generated by this technique are shown.

Day 3: Friday, August 6, 2004: Cbm And Unconventional Gas Development, Gary Bryner, Ken Wonstolen

Energy Field Tour 2004 (August 4-6)

19 pages (includes illustrations and maps).

Day 3: Friday, August 6, 2004: Air Quality And Energy Resources, University Of Colorado Boulder. Natural Resources Law Center

Energy Field Tour 2004 (August 4-6)

2 pages (includes illustration).

Day 2: Thursday, August 5, 2004: Valmont Power Plant, Valmont Power Plant

Energy Field Tour 2004 (August 4-6)

5 pages (includes illustrations).

Day 2: Thursday, August 5, 2004: Xcel Energy Lookout Dispatch Center, Doug Larson, United States. Department Of Energy

Energy Field Tour 2004 (August 4-6)

7 pages (includes illustrations and maps).

Agenda: Energy Field Tour 2004, University Of Colorado Boulder. Natural Resources Law Center

Energy Field Tour 2004 (August 4-6)

Tour (day trips along the Front Range, originating in Boulder) held August 4-6, 2004.

Summary: Assorted articles, maps, brochures, and other materials prepared for participants of the tour

Contents:

2004 energy field tour agenda -- Mission and vision of the Natural Resources Law Center -- Natural Resources Law Center, University of Colorado School of Law : a brief introduction -- Boulder area street map 4 -- Chatauqua area map -- [Bus] Route 203/225 : Boulder/Lafayette/Baseline -- Boulder-Lafayette via Baseline [bus schedules]

WEDNESDAY, AUGUST 4, 2004: OIL & GAS PRODUCTION FACILITIES AND PLATTEVILLE GAS PROCESSING FACILITY: 'Our next shortage', The Washington …

Day 1: Wednesday, August 4, 2004: Ponnequin Wind Farm, Western Resource Advocates

Energy Field Tour 2004 (August 4-6)

2 pages (includes illustration).

Day 1: Wednesday, August 4, 2004: Oil & Gas Production Facilities And Platteville Gas Processing Facility, Bruce Thompson

Energy Field Tour 2004 (August 4-6)

12 pages (includes illustrations and map).

Day 1: Wednesday, August 4, 2004: Calpine Rocky Mountain Energy Center, Calpine Rocky Mountain Energy Center

Energy Field Tour 2004 (August 4-6)

5 pages (includes illustrations).